1
Q
Humerus: Description
A
Single long bone of the arm Location: between the shoulder and the elbow
2
Q
Humerus: Gross Anatomy
A
- Proximal: Rounded head covered with articular cartilage, greater and lesser tubercles, intertubercular groove
- Mid: Surgical neck inferior to the tubercles, deltoid tuberosity, spiral groove from radial nerve
- Distal: condyle of the humerus which consists of: capitulum, trochlear, medial and lateral epicondyles, radial fossa, olecranon fossa, coronoid fossa
3
Q
Humerus: Articulations
A
- Proximal: the head of the humerus articulates with the glenoid of the scapula
- Distal: capitulum with the radial head, trochlear with the trochlear notch of the ulnar
4
Q
Humerus: Ligaments
A
- Superior, middle, inferior and spiral glenohumeral ligaments
- Radial and ulnar collateral ligaments
5
Q
Humerus: Relations
A
- Anterior: brachialis, bicep brachii, coracobrachialis
- Posterior: Profunda brachii, radial nerve, triceps brachii
- Lateral: deltoid
- Medial: brachial plexus, brachial artery, supratrochlear nodes
6
Q
Humerus: Neurovasculature
A
Blood supply:
- Anterior and posterior humeral circumflex arteries and veins
- Perforators from profunda brachii
Lymphatics:
- Supratrochlear and axillary nodes
Innervation:
- Radial nerve
7
Q
Humerus: Variants
A
- Supracondylar process
- Olecranon foramen
8
Q
Elbow Joint: Description
A
The elbow joint is a complex synovial joint between the arm and the forearm
Has a joint capsule
Synovial
9
Q
Elbow Joints: Movements
A
Combination hinge pivot joint:
Internal and external rotation of the arm
Flexion and extension of the arm
10
Q
Elbow Joint: Articulation
A
- Proximal head of the radius the capitulum of the humerus
- Trochlea notch of the ulnar with the trochlear of the humerus
- Proximal radial head the proximal radial notch of the ulnar
11
Q
Elbow Joint: Muscles
A
- Brachioradialis
- Biceps brachii
- Triceps brachii
12
Q
Elbow Joint: Ligaments
A
- Annular ligament
- Proximal radial and ulnar collateral ligament complexes
- Oblique cord- thickening of the supinator
13
Q
Elbow Joint: Fat Pads
A
- Coronoid and radial fossa fat pads anteriorly
- Olecranon fat pad posteriorly
14
Q
Elbow Joint: Neurovasculature
A
Blood supply:
- Anastomotic arcade formed from branches of the radial, ulnar and brachial arteries
Nerves:
- Median, radial, ulnar and musculocutaneous nerves
15
Q
Elbow Joints: Relations
A
- Anterior: biceps brachii tendon, brachialis muscle, median nerve, brachial artery
- Posteriorly: Olecranon bursae, triceps brachii tendon
- Laterally: Common extensor tendon, supinator muscle
- Medially: ulnar nerve
16
Q
Elbow Joint: Variants
A
- Variation in carry angle between males and females, females have larger angles usually
- Synovial folds
- Capitellar and olecranon pseudofacets
- Accessory ossicles: os supratrochlear dorsale, patella cubiti
17
Q
Glenohumeral Joint: Description
A
The shoulder joint also known as the gleno-humeral joint is a ball and socket synovial joint between the humerus and the glenoid.
18
Q
Glenohumeral Joint: Movement
A
- Most mobile joint in the body
- Flex/extension, int. ext. rotation, ab and adduction
19
Q
Glenohumeral joint: Articulation
A
Head of the humerus with the glenoid fossa of the scapula. The glenoid labrum adds depth to the glenoid fossa.
20
Q
Glenohumeral Joint: Capsule
A
- Attached to the margin of the glenoid fossa to the anatomical neck of the humerus, the long head of the biceps travels through it.
- It is re-enforced by the rotator cuff except inferiorly where it is at its weakest
21
Q
Glenohumeral Joint : Bursa
A
- Subacrominal – subdeltoid bursa
- Subscapular bursa (communicates with the joint by the foramen of Weitbrecht)
22
Q
Glenohumeral Joint: Ligaments
A
- Superior, middle and inferior glenohumeral ligaments
- Coracohumeral ligaments
- Transverse humeral ligament
23
Q
Glenohumeral Joint: Muscles
A
- abduction
- produced by the deltoid assisted by the supraspinatus
- adduction
- produced by the short scapular muscles (except supraspinatus) when the deltoid relaxes. Assisted by the pectoralis major and latissimus dorsi
- flexion
- clavicular head of the pectoralis major and the anterior fibers of the deltoid, assisted by the coracobrachialis and biceps
- extension
- latissimus dorsi, posterior fibers of the deltoid and the long head of the triceps
- rotation
- lateral rotation: infraspinatus and teres minor
- medial rotation: subscapularis and teres major
24
Q
Glenohumeral Joint: Neurovasculature
A
Arterial supply:
- Anterior and posterior humeral circumflex and subscapular arteries
Innervation:
- Axillary (C5-C6), suprascapular, subscapular, musculocutaneous nerves
Lymphatics:
- Axillary
25
Glenohumeral joint: Variants
* Buford complex – cord like middle glenohumeral ligament
* Os acrominale
* Capsule attached to labrum
* Long head of biceps insertion – glenoid, glenoid and labrum, labrum only
26
Biceps Brachii: Description
The biceps brachii muscle (also known simply as biceps) is a two-headed muscle in the anterior compartment of the arm that flexes at the elbow and supinates the forearm.
27
Biceps Brachii: Attachments
* Origin:
* Short head: coracoid process of the scapula
* Long head: supraglenoid tubercle of the scapula
* Insertion:
* Radial tuberosity of the proximal radius
28
Biceps Brachii: Innervation
musculocutaneous nerve
29
Biceps Brachii: Action
* arm abduction, arm adduction and ventral flexion
* supination
* flexion of the supinated forearm
30
Biceps Brachii: Variants
* Duplicated long head of biceps tendon: can mimic longitudinal tear
* Bifid/bifurcated insertion: anatomic variant that arises from persistent division between the short head and long head of the distal biceps brachii tendon
31
Brachial Plexus: Description
A plexus of nerves innervating the arm and part of the upper thorax
Location: in the neck extending into the axilla, posterior to the clavicle
Supply: motor and sensory to upper limb and upper thorax
32
Brachial Plexus: Components
Roots – C5 to T1
Trunks – upper C5-6, middle C7, lower C8-T1
Divisions – anterior and posterior
Cords – named to their relation to the axillary artery – medial, lateral, posterior
Branches:
* Axillary (C5-6)
* Musculocutaneous (C5-7)
* Radial (all)
* Medial (all)
* Ulnar (C7, 8 T1)
33
Brachial Plexus: Course
Emerges between the middle and anterior scalenes
Course intimately related to the axiallary artery
34
Brachial Plexus: Variant Anatomy
* ~50% Pre-fixed – C4 contribution or Post-fixed – T2 contribution
* Variation in branching patterns
35
Venous drainage of the left upper limb: Description
Venous drainage of the upper limb is a vascular system for the return of deoxygenated blood from the capillary beds of the upper limb to the heart via the superior vena cava.
36
Venous drainage of the left upper limb: Deep System
The deep veins are located under the deep fascia. They are typically paired and lie on either side of an artery from which they take their name (venae comitantes).
37
Venous drainage of the left upper limb: Hand
* Deep venous palmar arch - receives the palmar metacarpal veins, drains to the radial veins
* Radial veins - Receives the deep venous palmar arch, run with the the radial artery, drains into the brachial veins
* Ulnar veins – Receives the surficial venous palmar arch, runs with the ulnar artery, drains into the brachial veins
* Brachial veins – Origin at the union of the radial and ulnar veins, course following the brachial artery, ending at the inferior border of teres major, at this point the brachial veins join the basilic vein to form the axiliary vein
* Axillary veins – the axillary vein continues with the axillary artery and is joined by the cephalic vein, subscapular vein, circumflex humeral vein, lateral thoracic vein and thoraco-acromial vein. It terminates at the lateral margin of the first rib where it becomes the subclavian vein.
38
Venous drainage of the left upper limb: Superfical System
* Superficial venous palmer arch: accompanies the superficial palmer arch, drains the commo palmer digital veins, drains into the ulnar vein
* Dorsal venous network: formed from the dorsal metacarpal veins drains into the basilic and cephalic veins
* Cephalic – origin the dorsal venous plexus, runs up the superficial space of the lateral aspect of the arm, drains to the median cubital and axially vein
* Basilic – origin the dorsal venous network, up the superficial tissue of the medial aspect of the arm, also receives the median cubital vein, drains to the brachial veins mid arm
39
Carpal bones: Description
The carpal bones are the eight bones of the wrist. They form the articulation between the forearm and the hand.
40
Carpal Bones: Gross Anatomy
Unlike the metacarpals the carpals do not belong to individual fingers
The corresponding bones in the foot are the tarsals
Divided in 2 rows proximal and distal
**Proximal:**
* Scaphoid
* Lunate
* Triquetrum
* Pisiform (actually a sesamoid bone with the flexor carpi ulnaris tendon)
**Distal:**
* Trapezium
* Trapezoid
* Capitate
* Hamate
41
Carpal Bone: articulations
**Articulations:** All synovial
* Radiocarpal
* Intercarpal
* Carpometacarpal
42
Carpal Bones: Ligament
* Ulnar and radial collateral ligaments
* Palmar and dorsal radiocarpal ligaments
* Palmar and dorsal carpometacarpal ligaments
* Intercarpal ligaments
43
Carpal Bones: Vasculature
**Arterial:**
* Dorsal carpal arch, deep palmar arch, direct radial, and ulnar branches
**Venous:**
* Dorsal venous plexus, deep palmar venous arch, direct into the radial and ulnar veins
44
Carpal Bone: Variants
* Carpal coalition
* Bipartate scaphoid
* Type 1 or type 2 lunate
45
Lunate Bone: Description
The lunate is a bone of the proximal row of carpal bones
**Location:** between the scaphoid and triquetrum in the proximal carpal row
46
Lunate: Gross Features
* Semi-lunar in shape
* 4 articular facets (five in type 2)
47
Lunate: Articulations
* Radius
* Scaphoid
* Triquetrum
* Capitate
* Hamate (in type 2 lunate)
* Triangular fibrocartilage complex
48
Lunate: Ligaments
* Scapholunate
* Lunotriquetral
* Radiolunotriquetral
* Radioscapholunate
* Ulnolunate
49
Lunate: Vasculature
**Blood supply:**
Dorsal radiocarpal arch and dorsal intercarpal arch
**Venous:**
Dorsal venous plexus
50
Lunate: Variants
* Lunotriquetral coalition
* Os epilunatum
* Os hypolunatum
* Type 1 lunate – single distal articular facet for the capitate
* Type 2 lunate – additional distal articular facet for the hamate
51
Scaphoid: Description
* The scaphoid is a carpal bone
**Location:** Most lateral bone of the proximal carpal row
52
Scaphoid: Relations
* Lateral/dorsal: radial artery
* Medial: lunate and the carpal tunnel
* Distal: Trapezium
* Proximal: distal head of the radius
* Forms the radial portion of the carpal tunnel
53
Scaphoid: Gross anatomy
* Largest of the proximal row of carpal bones
* Boat shaped
* Dividable into proximal and distal poles, separated by a waist which is further dividable into proximal and distal waists
* Scaphoid tubercle is a bony prominence on the ventral surface serves as an attachment for the flexor retinaculum
54
Scaphoid: Articulation
Medial: Lunate
Proximal: Radius
Distal:
* Trapezium
* Trapizoid
* Medially with the capitate
55
Scaphoid: Ligaments
* Scapholunate
* Radioscapholunate
* Dorsal: Dorsal radiocarpal ligament
* Radial surface: radial collateral ligament
56
Scaphoid Vasculature
* Direct branches from the radial artery
* Dorsal radiocarpal arch
* Supply enters the distal pole to perfuse the proximal pole (risk of osteonecrosis with waist fracture)
* Venous drainage via the dorsal venous plexus and the radial veins
57
Scaphoid: variants
* Bipartite scaphoid
* Carpal coalition
* Scaphoid hypoplasia
58
Radius: Description
The radius is one of the two long bones of the forearm.
**Location:** Lateral in the forearm, extending from the elbow to the wrist
59
Radius: Features
Proximal: Head, neck and tuberosity insertion of the biceps brachii tendon
Mid: Shaft – thicker that the ulnar and becoming more thick distally
Distal: Carpal articular facet, ulnar notch, radial styloid, Lister’s tubercle (Dorsal)
60
Radius: Articulation
**Proximal:**
* Radial head with the capitulum of the humerus
* Radial head with the radial notch of the ulnar
**Distal:**
* Distal radius facet with the scaphoid and lunate
* Ulnar notch with the ulnar head
61
Radius: Ligaments
* Radial collateral ligaments of the elbow and wrist
* Radial annular ligament
* Interosseous membrane of the forearm
* Radial carpal ligaments (dorsal and palmar)
* Radioulnar ligaments (dorsal and palmer)
62
Radius: Neurovasculature
**Blood supply:**
Radial artery and vein
**Lymphatics:**
Supratrochlear
Axillary
**Innervation:**
Anterior and posterior interosseous nerves
63
Radius: Variants
Radio-ulnar synostosis
Hypoplastic or absent radius
64
Ulna: Description
The ulna is one of the two long bones of the forearm.
**Location:** medially with in the forearm
65
Ulna: Gross anatomy
Wider toward the proximal end
**Features:**
**Proximal:** Olecranon, trochlear notch, coronoid process, radial notch, sublime tubercle (medial) (flexor digitorum), ulnar tuberosity (brachialis)
**Mid:** Shaft
**Distal:** head, styloid process, fovea, groove for extensor carpi ulnaris
66
Ulna: Articulation
* Trochlear notch with the trochlear of the humerus
* Radial head with the radial notch
* Ulnar head with the ulnar notch (radius)
* Wrist via the triangular fibrocartilage complex
67
Ulna: Ligaments
Proximal: medial collateral ligament of the elbow, annular ligament
Medial: interosseous membrane, oblique cord
Distal: triangular fibrocartilage complex, ulnar collateral ligament of the wrist
68
Ulna: Variants
Ulnar variance (relative length difference between the radius and ulnar)
69
Ulna: Neurovasculature
**Blood supply:**
Ulnar and common interosseous artery
**Lymphatics:**
Supratrochlear
Axillary
**Innervation:**
Anterior and posterior interosseous nerves
70
Scapula: Description
The scapulae are bones of the pectoral girdle.
Location: Superior/posterior thoracic wall
Function: Movement and support of the shoulder girdle and shoulder
71
Scapula: Gross Anatomy
The scapula is a flat triangular bone with apex down.
**Features:**
* Inferior, lateral and superior angles
* Superior, medial and lateral borders
* Posteriorly the scapula is divided into a supraspinatus and infraspinatus fossa by the scapular spine
* Anteriorly there is the subscapular fossa
* Laterally is the glenoid fossa
* Superiorly is the acromion and coracoid process
72
Scapula Articulation
Acromion with the distal clavicular head, glenoid with the humeral head
73
Scapula: Ligaments
* Transverse scapula ligament across the scapular notch (with the suprascapular nerve below and the vessels above)
* Coracoacromial
* Coracoclavicular
* Coracohumeral
* Glenohumeral superior, middle and inferior
* Acromioclavicular
74
Scapula: vasculature
**Blood supply:**
Anastomotic network formed by:
* Suprascapular
* Dorsal scapular
* Subscapular
**Lymphatics:**
* Axillary
75
Scapula Muscles
* Rotator cuff + teres major
* Long head of the triceps and biceps
76
Scapula Variants
Os acrominale
77
Clavicle: Description
The clavicle is the only bone connecting the pectoral girdle to the axial skeleton. It is also the only horizontal long bone
78
Clavicle: Gross anatomy
S-shaped
**Features:**
**Medial:**
* Rounded medial end
* Costal tuberosity
* Groove for subclavius
**Distal:**
* Conoid tubercle
* Flat distal end
* Trapezoid line
79
Clavicle: articulations
* Medial end with the sternum
* Distal end with the acromion
80
Clavicle: Muscle
* Subclavius
* Pec. Major
* Sternocleidomastoid
* Deltoid
* Trapezius
* Sternohyoid
81
Clavicle: Ligaments
* Acromioclavicular
* Coracoclavicular (conoid and trapezoid)
* Sternoclavicular
* Costoclavicular
* Interclavicular
82
Clavicle: blood supply
Suprascapular artery
83
Clavicle: Variants
* Forked clavicle
* Supraclavicular foramen
84
Wrist Joint: Description
The wrist joint is a complex synovial joint
**Location:** between the forearm and the hand
**Movements:** flexion, extension, ulnar deviation, radial deviation, circumduction
85
Wrist Joint: Gross anatomy
Made up of the articulations between:
The distal radius head and ulnar notch
The ulnar and the triangular fibrocartilage complex (TFCC)
The radius and the scaphoid, lunate and triquetrum (condyloid joint)
The TFCC and the triquetrial bone
Special features:
Triangular fibrocartilage complex is a triangular cartilage disc between the ulnar and the triquetral bone
86
Wrist joint: Ligaments
* Ulnar collateral
* Radial collateral
* Radiocarpal ligaments (palmer and dorsal)
* Flexor and extensor retinacula
* Radioulnar ligaments dorsal and palmer
87
Wrist joint: Muscles
Flexor:
* Flexor carpi radialis and ulnaris
* Palmaris longus
* Flexor digitorium superficialis
* Flexor digitorium profundus
**Extensors:**
* Extensor carpi radialis longus and brevis
* Extensor carpi ulnaris
* Extensor digitorium
88
Wrist joint: Neurovasculature
**Blood supply:**
Radial and ulnar arteries
**Innervation:**
Anterior and posterior interosseous nerves
89
Wrist joint: Variants
Absent palmaris longus
Ulnar variance
90
Distal Radio-Ulnar Joint: Description
The distal radio-ulnar joint is a pivot joint between the distal radius and ulna
**Movement:** rotation of the distal radius
91
Distal Radio-Ulnar Joint: Gross anatomy
* Synovial joint between the ulnar notch on the radius and the ulna head
* The joint in stabilised by the TFCC
92
Distal Radio-Ulnar Joint: Muscles
**Pronation:** pronator quadratus and pronator teres
**Supination:** supinator and biceps brachii
93
Distal Radio-Ulnar Joint: Neurovasculature
**Blood supply:**
* Anterior and posterior interosseous
**Innervation:**
* Anterior and posterior interosseous nerves
94
Distal Radio-Ulnar Joint: Variants
Radial ulna length variance
95
Distal radio-ulnar joint: Ligaments
* Anterior and posterior distal radioulnar ligaments
* Interosseous membrane
96
Acromioclavicular joint: Description
The acromioclavicular (AC) joint is a plane synovial joint of the pectoral girdle.
97
Acromioclavicular joint: Gross anatomy
* Between the facets of the convex distal clavicle and flat medial acromion.
* The articular surfaces are lined with hyaline cartilage.
* A fibrocartilaginous wedge-shaped articular disc separates the two articular surfaces.
* A weak, synovium-lined joint capsule is attached to the articular margins and is reinforced superiorly by blending fibres of the trapezius muscle.
98
Acromioclavicular joint: Ligaments
Static stabilisation is provided by:
* coracoclavicular ligaments
* superior and inferior acromioclavicular ligaments
99
Acromioclavicular joint: Neurovasculature
**Blood supply**
Suprascapular and thoracoacromial arteries
**Innervation**
Axillary, suprascapular and lateral pectoral nerves
100
Acromioclavicular joint: Variants
* Acromioclavicular joint configuration
* Os acromiale
101
Sternoclavicular joint: Description
The sternoclavicular joint is a synovial joint between the medial clavicle, manubrium and the first costal cartilage that joins the upper limb with the axial skeleton.
102
Sternoclavicular joint: Gross anatomy
* Saddle joint between the medial clavicle and the clavicular notch of the sternum
* The articular surfaces are covered with fibrocartilage (rather than hyaline cartilage as in most other synovial joints). The joint space is divided into two separate recesses by a fibrocartilage articular disc.
103
Sternoclavicular joint: Ligaments
Due to the non-congruent articular facets, much of the joint stability comes from surrounding ligaments:
* anterior and posterior sternoclavicular ligament
* interclavicular ligament
* costoclavicular ligament
104
Sternoclavicular joints: relations
* Anteriorly: sternocleidomastoid muscle
* Posteriorly: sternohyoid muscle, sternothyroid muscle, brachiocephalic veins, the origin of the great vessels
105
Sternoclavicular joint: Neurovasculature
**Blood supply**
Arterial supply: internal thoracic and suprascapular arteries
**Innervation**
Medial supraclavicular and subclavian nerves
106
Sternoclavicular joint: Variants
* ~2.5% of the population have an inferior facet for articulation with the first rib
* perforation of the articular disc, where the joint recesses are in communication
107
Transverse carpal ligament: Description
The flexor retinaculum (also known as the transverse carpal ligament) is a rectangular-shaped fibrous band located at the ventral aspect of the wrist.
108
Flexor retinaculum: Gross anatomy
* Between the scaphoid tubercle and the ridge of the trapezium to the pisiform and the hook of the hamate.
* The flexor retinaculum encloses and forms the roof of the carpal tunnel.
* The ulna aspect of the flexor retinaculum forms the floor of Guyon's canal.
* It has superficial and deep layers, which are separate on the radial aspect, containing the tendon of flexor carpi radialis.
109
Flexor retinaculum: Attachments
Proximally: deep fascia of the forearm
Distally: palmar aponeurosis
110
Flexor retinaculum: Relations
Inferiorly: contents of the carpal tunnel
Superiorly:
* ulnar artery and nerve (in Guyon's canal)
* palmar cutaneous branch of the median and ulnar nerves
* palmaris longus tendon
* superficial palmar branch of the radial artery
* origins of thenar and hypothenar muscles
between superficial and deep layers: flexor carpi radialis
111
Flexor Retinaculum: Variants
Radial aspect of the flexor retinaculum may be pierced by the median nerve
112
Medial collateral ligament of the elbow
Runs from the humerus to the ulna and is composed of three parts (TAP):
* Anterior bundle
* Posterior bundle
* Transverse bundle
**Variant anatomy:**
Accessory ligament
113
Lateral collateral ligament of the elbow
Y-shaped ligamentous complex composed of three parts (LAR):
* Annular ligament (around the radial head)
* Radial collateral ligament
* Lateral ulnar collateral ligament
**Variant anatomy:**
Accessory lateral collateral ligament
114
Glenoid labrum: Description
The glenoid labrum is a fibrocartilaginous structure that attaches as a rim to the articular cartilage of the glenoid fossa and serves to deepen and increase the surface area.
**Function:** deepen the glenoid, stablise the shoulder
115
Glenoid labrum: Gross anatomy
~4mm thick and it is round or triangular in cross section
116
Glenoid Labrum: Attachments
The capsule of the glenohumeral joint attaches to the glenoid labrum. The glenoid labrum is continuous with:
* Superiorly: the long head of the biceps
* Anteriorly: anterior band of the inferior glenohumeral ligament
117
Glenoid Labrum: Neurovasculature
**Blood supply:**
* Out labrum is vascular inner is avascular
* Anterior and posterior humeral circumflex
* Subscapular artery
**Innervation:**
Axillary, suprascapular, subscapular and musculotendinous nerves
118
Glenoid Labrum: Variants
* Round or triangular labrum
* Buford complex
* Sublabral foramen
* Variation in the capsule insertion (1,2,3)
119
Intrinsic muscles of the hand
**All for one and one for all:**
* A: abductor pollicis brevis
* F: flexor pollicis brevis
* O: opponens pollicis
* A: adductor pollicis
* O: opponens digiti minimi
* F: flexor digiti minimi
* A: abductor digiti minimi
120
Anterior compartment of the forearm: Description
The forearm is divided into the anterior compartment and the posterior compartment by the deep fascia, lateral intermuscular septum and the interosseous membrane between the ulna and radius.
121
Anterior compartment of the forearm: Muscles
The eight muscles located in the anterior compartment of the forearm can be divided into three layers - superficial, intermediate and deep.
**Superficial layer:**
* Flexor carpi ulnaris (FCU)
* Palmaris longus (PL)
* Flexor carpi radialis (FCR)
* Pronator teres (PT)
**Intermediate layer:**
* Flexor digitorum superficialis (FDS)
**Deep layer:**
* Flexor digitorum profundus (FDP)
* Flexor pollicis longus (FPL)
* Pronator quadratus (PQ)
122
Anterior compartment of the forearm: Neurovasculature
**Arterial:**
Ulnar artery, radial artery
**Innervation:**
Median nerve
123
Posterior compartment of the forearm: Description
The forearm is divided into the posterior compartment and the anterior compartment by the deep fascia, lateral intermuscular septum and the interosseous membrane between the ulna and radius.
124
Posterior compartment of the forearm: Muscles
The posterior compartment of the forearm contains 11 muscles, divided into deep and superficial layers.
**Superficial**
* mobile wad of Henry
* Brachioradialis
* extensor carpi radialis longus (ECRL)
* extensor carpi radialis brevis (EXRB)
* Extensor digitorum (ED)
* Extensor digiti minimi (EDM)
* Extensor carpi ulnaris (ECU)
**Deep**
* Supinator
* Extensor pollicis longus (EPL)
* Extensor pollicis brevis (EPB)
* Abductor pollicis longus (APL)
* Extensor indicis (EI)
125
Posterior compartment of the forearm: Neurovasculature
**Blood supply**
Anterior and posterior interosseous arteries, which are branches of the short common interosseous artery arising from the proximal ulnar artery.
**Innervation**
All muscles in the extensor compartment are supplied by the radial nerve.
126
Triceps Brachii: Description
The triceps brachii, which often referred to simply as the triceps is a three-headed muscle in the posterior compartment of the arm.
Actions
* extensor of the elbow joint
* assists in extension of the shoulder joint (long head only)
127
Triceps brachii: Attachments
**Origin:**
* Long head: infraglenoid tubercle of the scapula
* Medial head: posterior humerus
* Lateral head: posterior and lateral humerus
**Insertion:** proximal olecranon of the ulna and deep fascia of arm
128
Triceps brachii: Neurovasculature
**Arterial:**
Branches of deep brachial artery
**Innervation:** radial nerve, branches of ulnar nerve
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Triceps Brachii: Variants
* a patella cubiti may be present (very rare)
* 4th head from medial humerus
* slip termed dorso-epitrochlearis extending between triceps and latissimus dorsi
130
Deltoid: Description
The deltoid muscle is the largest of the shoulder muscles. The muscle is composed of three heads (clavicular, acromial and spinous), although electromyography suggests that there are at least seven control regions that could act independently
**Action:**
* clavicular part: ventral flexion and abduction of the arm
* acromial part: abduction of the arm
* spinous part: dorsal flexion and external rotation of the arm
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Deltoid: Attachments
**Origin:** lateral 1/3 of the clavicle, acromion, lateral 2/3 of the scapula spine
**Insertion:** deltoid tuberosity of the humerus
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Deltoid: Neurovasculature
**Innervation:** axillary nerve (C5-6)
**Arterial supply:**
* Acromial and deltoid branches of the thoracoacromial artery
* Anterior and posterior humeral circumflex arteries
* Subscapular artery
* Deltoid branch of profunda brachii
133
Coracobrachialis: Description
The coracobrachialis is one of the three muscles of the anterior compartment of the arm. It sits beneath the biceps brachii, inserting via a flat tendon into the medial shaft of the humerus.
**action:** ventral shoulder flexion and shoulder adduction
134
Coracobrachialis: Attachments
**origin:** coracoid process of scapula
**insertion:** via a flat tendon onto the midportion of the medial surface of humerus
135
Coracobrachialis: Innervation
**innervation:** musculocutaneous nerve (C6 and C7)
136
Brachialis: Description
The brachialis muscle (brachialis) is one of the three muscles of the anterior compartment of the arm. It is only involved in flexion at the elbow and therefore the strongest flexor at the elbow, compared with the biceps brachii which is also involved in supination because of its insertion on the radius.
**Action:** flexion at the elbow
137
Brachialis: Attachments
**Origin:** lower portion of the anterior surface of the humerus
**Insertion:** ulna tuberosity and coronoid process of the ulna
138
Brachialis: Innervation
**Innervation:** musculocutaneous nerve and radial nerve (proprioceptive branch)
139
Brachialis: Variants
Although rare, supernumerary heads of brachialis have been reported and may cause entrapment of the median nerve and/or brachial artery.
140
Rotator Cuff: Description
The rotator cuff is a group of four muscles and their tendons that play an important role in the stabilisation of the shoulder
141
Supraspinatus
**origin:** supraspinous fossa of the scapula
**insertion:** greater tuberosity of the humerus
**innervation:** suprascapular nerve (C5-6)
**arterial supply:** suprascapular and dorsal scapular arteries
**action:** shoulder abduction
142
Infraspinatus
**origin:** infraspinatus fossa of the scapula
**insertion:** greater tuberosity of the humerus
**innervation:** suprascapular nerve (C5-6)
**arterial supply:** suprascapular and circumflex scapular arteries
**action:** external rotation
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Teres minor
**origin:** lateral border of the scapula
**insertion:** greater tuberosity of the humerus
**innervation:** axillary nerve (C5-6)
**arterial supply:** circumflex scapular artery
**action:** external rotation, weak adductor of the humerus, stabilises the shoulder joint, holds the head of the humerus down against the upward pull of the deltoid during abduction
144
Subscapularis
**origin:** subscapular fossa of the scapula
**insertion:** lesser tuberosity of the humerus
**arterial supply:** suprascapular, axillary and subscapular arteries 1
**innervation:** upper and lower subscapular nerves (C5-6)
**action:** internal rotation
145
Ligaments of the rotator cuff
Coracohumeral ligaments
Glenohumeral ligaments (superior, middle and inferior)
146
Axillary Nerve: Description
The axillary nerve is one of five terminal branches of the brachial plexus, supplying motor and sensory branches to the shoulder.
147
Axiliary nerve: origin
* The axillary nerve is one of two terminal branches of the posterior cord of the brachial plexus. It receives contributions from C5-6 nerve roots.
148
Axillary Nerve: Course
* Posterior to the axillary artery
* Inferior to the shoulder joint
* Exiting the axilla through the quadrangular space
149
Axilliary nerve: Branches
* Muscular branches: deltoid and teres minor muscles
* Articular branches to the glenohumeral joint
* Superior lateral cutaneous nerve of the arm: skin overlying the deltoid muscle
150
Median Nerve: Description
The median nerve is one of the five main nerves originating from the brachial plexus and provides motor and sensory innervation to parts of the forearm and hand.
151
Median Nerve: Origin
* lateral root: lateral cord of the brachial plexus
* medial root: medial cord of the brachial plexus
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Median Nerve: Course
* laterally to the axillary artery,
* descends in the arm between biceps brachii and triceps brachii muscles,
* courses through the forearm with the ulna nerve and vessels before entering the carpal tunnel to the hand
153
Median Nerve: Branches and supply
**Major branches:**
* anterior interosseous nerve
* palmar cutaneous branch
* motor branch in the hand
**motor supply:** flexor compartment of the forearm, thenar and intrinsic hand muscles
**sensory supply:** palmar aspect of the thumb, index, middle finger and radial half of the ring finger
154
Median Nerve: Variant Anatomy
* high division or bifid median nerve
* median nerve (normal or bifid) may be accompanied by a persistent median artery of the forearm
* accessory branches arising proximal or distal to the carpal tunnel
* variant course of thenar branch 5
* aberrant origin to the motor branch (under the flexor retinaculum or through the flexor retinaculum)
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Radial Nerve: Description
The radial nerve is one of five main branches of the brachial plexus. It provides motor and sensory innervation to the arm and forearm and sensory innervation to the hand.
156
Radial Nerve: Origin
(C5 to T1)
One of the two posterior cords of the brachial plexus
157
Radial Nerve: Course
* posteromedially with the axillary vessels
* behind the humerus
* then anteriorly towards the elbow where it divides into superficial and deep branches
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Radial Nerve: Supply and Branches
**Terminal branches:** posterior interosseous (deep) and superficial radial nerves
**Motor:** elbow, wrist and finger extension
**Sensory:** dorsal aspect of the thumb, index and middle fingers
159
Radial Nerve: Variants
Arcade of Frohse
160
Ulnar Nerve: Description
The ulnar nerve is one of the terminal branches of the brachial plexus
Function: Motor and sensory supply to the forearm and hand
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Ulnar Nerve: origin
**Origin:** Terminal branch of the medial cord (C8 to T1)
162
Ulnar Nerve: Course
**Arm:**
In the arm the ulnar nerve medial to axillary and brachial arteries
It passes into the posterior compartment running with the superior ulnar collateral.
It passes posterior to the medial epicondyle in the cubital tunnel
**Forearm:**
Enters the forearm between the two heads of flexor carpi ulnaris (FCU)
Running medial to the ulnar artery
**Hand:**
Enters the hand via Guyon’s canal.
Dividing into a deep and superficial branch
163
Ulnar Nerve: Supply
**Motor:**
Flexor carpi ulnaris, flexor digitorum profundus (medial half)
Hypothenar muscles
3rd and 4th lumbricals
Flexor pollicis brevis
Palmaris brevis
**Sensory:**
Articular – elbow, wrist, carpal and phalangeal joints
Cutaneous innervation to the ulnar aspect of the hand, the 5th and medial 4th fingers
164
Ulnar Nerve: Variants
Supply from nerve roots above and below
Cubital and Guyon’s canal syndrome
165
Musculocutaneous Nerve
The musculocutaneous nerve is one of five major branches of the brachial plexus and supplies motor innervation to the arm and sensory innervation to the forearm.
166
Musculocutaneous Nerve: Origin
* The musculocutaneous nerve is one of two terminal branches of the lateral cord of the brachial plexus (along with the lateral root of the median nerve). It receives fibres from the C5-7 nerve roots.
167
Musculocutaneous Nerve: Course
* Laterally away from the axillary artery
* pierces (and supplies) the coracobrachialis muscle
* descends towards the elbow between biceps brachii and brachialis muscles.
* lateral to the biceps tendon as the lateral cutaneous nerve of the forearm, which is simply the sensory continuation of the musculocutaneous nerve
168
Musculocutaneous Nerve: Branches+ supply
* Muscular branches: anterior compartment of the arm (coracobrachialis, biceps brachii and brachialis muscles)
* Articular branches: shoulder and elbow joints
* Lateral cutaneous: lateral aspect of the forearm
169
Musculocutaneous Nerve: Variants
* Coursing behind coracobrachialis
* May transmit fibres to/from median nerve
Supply of pronator teres
170
Arterial Supply of the hand
The arterial supply of the hand is the vascular system that supplies oxygenated blood to the hand. Formed from the branches and distal continuations of the radial and ulnar arteries.
171
Arterial supply of the hand: Gross anatomy
The vascular network can be dived into palmer and dorsal components
172
Superficial Palmar arch
* Superficial palmer arch – branch of the ulnar artery, forms distal to the flexor retinaculum, incomplete in 2/3 of people, arch lies across the centre of the palm
* Palmer digital artery – branch of the superficial palmer arch, runs of the ulnar side of the 5th finger
* Common palmer digital arteries – three of, origin superficial palmer arch, run between the metacarpal 2-5, divide to form the two proper palmer digital arteries each
* Proper palmer digital arteries – origin common palmer digital arteries, supplies digits 2-4
* Superficial palmer branch of the radial artery – Origin radial artery branch prior to the flexor retinaculum, supplies the thenar muscle, connects with the superficial palmer arch in 1/3 of people
173
Deep palmar arch
* Princeps pollicis artery – branch of the radial artery, travels along the first metacarpal, divides into two palmer digital branches at the metacarpal head
* Radialis indicis artery – origin radial artery, supplies the radial aspect of the index finger
* Deep palmer arch – Continuation of the radial artery that anastomoses with the deep branch of the ulnar artery, often the arch is complete unlike the superficial arch
* Palmer metacarpal arteries – three of, branches of the deep palmer arch, at the metacarpal heads they anastomose with the common palmar digital branches of the superficial arch, they also perforate the interosseous spaces to anastomose with the dorsal metacarpal arteries
174
Dorsal arterial supply of the hand
* Dorsal carpal arch – connection of the dorsal carpal branch of the radial artery and the dorsal carpal branch of the ulnar artery
* Dorsal metacarpal arteries – branches of the dorsal carpal arch, split at the webs to supply the dorsal sides of the fingers, they anastomose with the deep palmer arch via the palmer metacarpal arteries
175
Hand arterial supply variants
Deep arch is incomplete in 2/3 people
176
Subclavian artery
**Origin:** the left subclavian artery originates from the aortic arch (3rd branch)
**Course:** through the superior thoracic aperture posterior to the subclavian veins
**Termination:** becomes the axillary artery at the lateral border of the third rib
177
Subclavian artery Branches
1st part:
Vertebral
Internal thoracic
Thyrocervical trunk
2nd part:
Costocervical trunk
Dorsal scapular
178
Axillary Artery
**Origin:** continuation of the subclavian artery from the lateral boarder of the first rib
**Course:** Passes behind the mid point of the clavicle, divided into 3 parts:
Proximal to pec. Minor
Posterior to pec.minor
Distal to pec. Minor
179
Axillary artery: Branches
1st:
Superior thoracic
2nd:
Thoracoacromial artery
Lateral thoracic artery
3rd
Subscapular artery
Anterior humeral circumflex
Posterior humeral circumflex
180
Brachial Artery
**Origin:** continuation of the axillary artery distal to teres major
**Course:** Medial aspect of the upper arm
**Termination:**
Bifurcation in the cubital fossa to for the radial and ulnar arteries
181
Brachial artery: Branches
* Profunda brachii
* Nutrient vessels to the humerus
* Superior and inferior ulnar collateral arteries
182
Radial artery
**Origin:** cubital fossa terminal branch of the brachial artery
**Course:** Runs along the radial aspect of the anterior compartment of the forearm, under brachioradialis and lateral to flexor carpi radialis, passes over the dorsal aspect of the scaphoid, forming the deep palmar arch of the hand
**Termination:** Anastomosis with the ulnar artery
183
Radial artery: Branches
* Palmar carpal branch
* Dorsal carpal branch
* Superficial palmar branch
* Princeps pollicis artery
* Radialis indicis artery
184
Ulnar artery
**Origin:** bifurcation of the brachial artery in the cubital fossa
**Course:** courses along tha ulnar aspect of the forearm deep to the flexor muscles, enters the hand through Guyon’s canal
**Termination:** superficial palmer arch
185
Ulnar artery: Branches
* Anterior and posterior ulnar recurrent arteries
* Palmer carpal arch
* Common interosseous artery
* Superficial palmer arch
186
Left subclavian artery
Subclavian artery is a large artery that supplies the arm, neck, anterior thorax, posterior circulation of the brain
**Function:** Deliver oxygenated blood
**Location:**
Beneath the clavicles bilaterally
187
Left subclavian artery
**Origin:** the third branch on the aortic arch (normal configuration)
**Course:** Ascends through the superior thoracic aperture, posterior to the brachiocephalic veins, between the anterior and middle scalene muscles
**Divided into 3 parts:**
1st part from origin to the medial edge of scalenus anterior
2nd part to the lateral edge of scalenus anterior
3rd part to the lateral boarder of the first rib
**Termination:** continues as the axillary artery
188
Left subclavian artery: Branches
**1st part:**
* Vertebral
* Internal thoracic
* Thyrocervical trunk
**2nd part:**
* Costocervical trunk
* Dorsal scapular
**3rd part:**
* None
189
Left subclavian artery: Variants
* Origin variants
* Aberrant right subclavian (between trachea and oesophagus)
* Order of branches may vary
* Origin of vertebral artery from the aorta
190
Lymph nodes of the upper limb
Lymphatic drainage of the upper limb is via series of deep and superficial channels that ultimately drain into the axillary lymph nodes.
191
Lymph nodes of the upper arm: Gross anatomy
Lymph from the hand and forearm drain from lymphatic plexuses via superficial channels that accompany the basilic and cephalic veins to a series of nodes around the elbow:
* superficial and deep cubital lymph nodes
* epi/supratrochlear lymph node(s)
* one-to-five nodes lying medial to the brachial vein, just superior to the medial epicondyle of the humerus
There are also deep channels that accompany the arteries and drain via the occasional deep lymph node accompanying arteries in the forearm to the axillary nodes.
Lymph then drains up the arm, passing through a few deep brachial lymph nodes and deltopectoral lymph node(s) with the cephalic vein at the deltopectoral groove, before draining into:
* Infraclavicular lymph nodes: predominantly lateral upper limb and lateral two digits
* Axillary lymph nodes: predominantly medial upper limb and medial three digits
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Cubital fossa: Description
The cubital fossa is a triangular space which forms the transition between the arm and the forearm. It is located anterior to the elbow joint.
193
Cubital fossa: Boundaries
* superior: the line joining the medial and lateral humeral epicondyles
* lateral: medial border of brachioradialis
* medial: lateral border of pronator teres
* apex: formed by the meeting of the lateral and medial boundaries
* roof: deep fascia of forearm reinforced medially by the bicipital aponeurosis
* floor: brachialis muscle (medial), and supinator muscle (lateral)
194
Cubital fossa: Contents
* M: median nerve
* B: brachial artery
* T: tendon of biceps
* R: radial nerve
* P: posterior interosseous branch of radial nerveCarpal tunnel (2017)
195
Axilla: Description
The axilla is a space located between the upper limb and the neck and thorax, which permits the passage of the major neurovascular structures.
196
Axilla: Gross anatomy
The axilla is pyramidal in shape with its apex opening superiorly into the base of the neck between the subclavius muscle, first rib and the clavicle.
The base/floor is composed of tough axillary fascia
197
Axilla: Boundaries
* anteriorly: pectoralis major, pectoralis minor, clavipectoral fascia, clavicle
* posteriorly: subscapularis, teres major, scapula, latissimus dorsi (forming the posterior axillary fold)
* medially: serratus anterior overlying chest wall to the level of the 4th rib
* laterally: intertubercular groove of the humerus
198
Axilla: Contents
The axilla has an abundance of fat, which contains the following structures:
* axillary artery
* axillary vein
* brachial plexus
* axillary lymph nodes
* tendons of the long and short heads of biceps
* pectoralis minor
* Coracobrachialis
199
Extensor compartments of the wrist
The extensor tendons at the level of the wrist are divided into six extensor compartments that are designated by Roman numerals from lateral to medial:
* I: extensor pollicis brevis, abductor pollicis longus
* II: extensor carpi radialis longus, extensor carpi radialis brevis
* III: extensor pollicis longus◦compartments 2 and 3 are divided by Lister's tubercle of the distal radius
* IV: extensor digitorum, extensor indicis
* V: extensor digiti minimi
* VI: extensor carpi ulnaris
Anatomy
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