Pectoralis minor
Shoulder girdle
Crosses shoulder joint
Origin - ribs 3-5
Insertion - coracoid process of scapula
Action - Origin fixed: protraction and downward rotation of scapula.
Insertion fixed: elevates ribs when breathing
Trapezius
Shoulder girdle
Origin: back of skull, C7 and T1-12
Insertion: spine of scapula and lateral edge of clavicle
Action:
Upper fibres - elevate the shoulder girdle and help with neck extension
Middle fibres - retract the shoulder girdle
Lower fibres - depress the shoulder girdle
Muscle as a whole - upwardly rotates scapula
Rhomboids
Shoulder girdle
Origin: spinous processes of C7 and T1-5
Insertion: medial border of the scapula
Action: retracts scapula, downwardly rotates scapula
Levator Scapulae
Shoulder girdle
Origin: transverse processes of cervical vertebrae (C1-4)
Insertion: medial border of the scapula, between the superior angle and the root of the spine of the scapula
Action: Origin fixed - elevates scapula and assists in downward rotation of the scapula
Insertion fixed - laterally flexes the neck
Serratus anterior
Shoulder girdle
Origin: front of ribs 1-8
Insertion: anterior surface of the medial border of the scapula
Action: protracts scapula and upwardly rotates the scapula (with trapezius)
Pectoralis major
Shoulder joint
Origin: clavicle, sternum and cartilage of ribs 1-6
Insertion: humerus
Action: shoulder horizontal flexion, adduction, medial rotation
Teres major
Shoulder joint
Origin: lateral border of the scapula near the inferior angle
Insertion: humerus (proximal, anterior)
Action: medial rotation, adduction and extension of the shoulder joint
Latissimus dorsi
Shoulder joint
Origin: via the TLF from spinous process of T6-12, lumbar and sacral vertebrae and iliac crest. Also the lower 3 ribs and inferior edge of scapula.
Insertion: top of humerus anterior
Action: origin fixed - adducts and extends the arm. Assists in medial rotation of the arm. Depresses the shoulder girdle via the insertion on the humerus. Insertion fixed - tilts the pelvis forward.
TLF - thoracolumbar fascia
Deltoids
Shoulder joint
Origin: Anterior- clavicle
Medial -acromion process
Posterior head - spine of scapula
Insertion - lateral surface of humerus
Action - anterior fibres flex the shoulder and assist in horizontal flexion and medial rotation. Medial fibres abduct shoulder (but others too). Posterior fibres extend the shoulder and assist in horizontal extension.
Biceps brachii
Arm
Origin: scapula
Insertion: top of radius and biciptal aponurosis to medial part of forearm
Crosses: shoulder and elbow
Action: flexes elbow
Supinates forearm
Assists in shoulder flexion
Brachialis
Arm
Origin: humerus
Insertion: ulna
Crosses: elbow
Action: flexes elbow
Brachioradialis
Arm
Origin: laterally at distal end of humerus
Insertion: laterally at distal end of radius
Joint crossed: elbow
Action: flexion when the forearm is semi-pronated
Assists other flexors
Triceps brachii
Arm
Origin: long head - scapula just above shoulder joint
Other two heads - posterior of humerus
Insertion: olecranon of ulna
Crosses: elbow and shoulder
Action: extends elbow
Assists in shoulder extension and adduction (long head only)
Supraspinatus
Rotator cuff
Shoulder
Origin: superior to the spine of scapula
Insertion: superiorly on the head of humerus
Action: assists deltoid in abduction of arm
Stabilises the shoulder joint, helps prevent downward dislocation. A weak lateral rotator.
Subscapularis
Rotator cuff
Shoulder
Origin: anterior surface of scapula
Insertion: Anteriorly on head of humerus
Action: Rotates arm medially
Infraspinatus
Rotator cuff
Shoulder
Origin: inferior spine of scapula
Insertion: laterally on head of humerus
Action: rotates arm laterally
Teres minor
Rotator cuff
Shoulder
Origin: lateral border of the scapula near the inferior angle
Insertion: laterally on the head of the humerus
Action: rotates the arm laterally and stabilises the joint
Iliocostalis group (ES)
Vertebral column
Origin: Ribs and iliac crest
Insertion: transverse processes of the cervical vertebrae and ribs superior to origin
Crosses: vertebrae
Action: extends spine
Longuissimus group (ES)
Vertebral column
Origin: transverse process of cervical, thoracic and lumbar vertebrae
Insertion: transverse processes of superior vertebrae of origin
Crosses: vertebrae
Action: extends head and rotates to same side. Extends the spine
Spinalis (ES)
Vertebral column
Origin: Spinous processes of cervical, thoracic and lumbar vertebrae
Insertion: spinous processes of superior vertebrae to origin
Crosses: vertebrae
Action: extends spine
Quadratus lumborum
Vertebral column
Origin: iliac crest and iliolumbar fascia
Insertion: upper 4 lumbar vertebrae and lower margin of 12th rib
Crosses: intervertebral joints of lumbar vertebrae
Actions: unilateral concentric contraction - lateral flexion of the lumbar spine
Unilateral isometric contraction - prevents lateral flexion of lumbar spine
Bilateral eccentric contraction - assists in preventing hyperflexion of the lumbar spine
Multifidus
Vertebral column
Origin: sacrum and transverse processes of vertebrae
Insertion: spinous processes 2-4 vertebrae superior to the origin
Crosses: intervertebral joints of the vertebrae column (VC)
Actions: extension of VC (bilaterally). Assists in rotation of the VC (unilaterally). Assists in lateral flexion of the spine (unilaterally).
Transverse abdominus
Anterior abdominal wall
Origin: thoracolumbar fascia, cartilage of lower 6 ribs & iliac crest
Insertion: linea alba
Crosses: intervertebral joints of lumbar vertebrae
Action: compression of abdominal cavity and increases abdominal pressure. Stabilises lumbar spine by creating tension though TLF and increasing IAP.
Rectus abdominus
Anterior abdominal wall
Origin: pubis and symphysis pubis
Insertion: cartilage of ribs 5-7 and base of sternum
Crosses: intervertebral joints of lumbar and thoracic vertebrae
Action: flexion of the vertebral column
