Muscles of the Shoulder Girdle
Muscles of the Shoulder Girdle
|
Muscle |
Origin |
Insertion |
Action |
Innervation |
|
Trapezius |
SP C7–T12 |
Clavicle, scapula |
Rotating scapula |
Cranial nerve XI |
|
|
|
(acromion, SP) |
|
|
|
Latissimus dorsi |
SP T6–S5, ilium |
Humerus (ITG) |
Extending, adducting, internally rotating humerus |
Thoracodorsal nerve |
|
Rhomboid major |
SP T2–T5 |
Scapula (medial border) |
Adducting scapula |
Dorsal scapular nerve |
|
Rhomboid minor |
SP C7–T1 |
Scapula (medial spine) |
Adducting scapula |
Dorsal scapular nerve |
|
Levator scapulae |
Transverse process C1–4 |
Scapula (superior medial) |
Elevating, rotating scapula |
C3, C4 nerves |
|
Pectoralis major |
Sternum, ribs, clavicle |
Humerus (lateral ITG) |
Adducting, internally rotating arm |
Medial and lateral pectoral nerves |
|
Pectoralis minor |
Ribs 3–5 |
Scapula (coracoid) |
Protracting scapula |
Medial pectoral nerve |
|
Subclavius |
Rib 1 |
Inferior clavicle |
Depressing clavicle |
Upper trunk nerves |
|
Serratus anterior |
Ribs 1–9 |
Scapula (ventral medial) |
Preventing winging |
Long thoracic nerve |
|
Deltoid |
Lateral clavicle, scapula |
Humerus (deltoid tuberosity) |
Abducting arm |
Axillary nerve |
|
Teres major |
Inferior scapula |
Humerus (medial ITG) |
Adducting, internally rotating, extending arm |
Lower subscapular nerve |
|
Subscapularis |
Ventral scapula |
Humerus (lesser tuberosity) |
Internally rotating arm, providing anterior stability |
Upper and lower subscapular nerves |
|
Supraspinatus |
Superior scapula |
Humerus (GT) |
Abducting and externally rotating arm, providing |
Suprascapular nerve |
|
|
|
|
stability |
|
|
Infraspinatus |
Dorsal scapula |
Humerus (GT) |
Providing stability, externally rotating arm |
Suprascapular nerve |
|
Teres minor |
Scapula (dorsolateral) |
Humerus (GT) |
Providing stability, externally rotating arm |
Axillary nerve |
GT, Greater tuberosity; ITG, intertubercular groove; SP, spinous process.
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FIG. 2.4 Borders of the key spaces and intervals around the shoulder, including the suprascapular nerve course as well as the quadrangular space and triangular space/interval.
Table 2.3
Shoulder Spaces
|
Space Borders Nerve Artery |
|||
|
Quadrangular (quadrilateral) space |
Superior: lower border of teres minor Inferior: upper border of teres major Medial: long head of triceps Lateral: surgical neck of humerus |
Axillary |
Posterior humeral circumflex |
|
Triangular space |
Superior: lower border of teres minor Inferior: upper border of teres major Lateral: long head of triceps |
|
Circumflex scapular |
|
Triangular interval |
Superior: lower border of teres major Medial: long head of triceps Lateral: shaft of humerus |
Radial |
Profunda brachii |