1. Muscles of the Back By Prof Saeed A. Abouel Makarem

2. Cutaneous Nerves of the Back of the Neck Back of the neck is supplied by dorsal Back of the neck is supplied by dorsal rami of the cervical nerves rami of the cervical nerves EXCEPT the 1 st & 8 th (which has no cutaneous branches). EXCEPT the 1 st & 8 th (which has no cutaneous branches).

3. N.B. N.B. Dorsal ramus Dorsal ramus of C1 & C 8 of C1 & C 8 has no has no Cutaneous Cutaneous Branches. Branches.

4. Muscles of back are arranged in 4 layers. Muscles of back are arranged in 4 layers. 1 st. Layer : 1 st. Layer : 1- Trapezius. 1- Trapezius. 2- Latissimus Dorsi. 2- Latissimus Dorsi. 2nd Layer: 2nd Layer: 1- Levator Scapulae. 1- Levator Scapulae. 2- Rhomboideus minor. 2- Rhomboideus minor. 3- Rhomboideus major. 3- Rhomboideus major. Also the 2 nd layer contains 2 other muscles: Also the 2 nd layer contains 2 other muscles: 4- Serratus posterior superior. 4- Serratus posterior superior. 5- Serratus posterior inferior 5- Serratus posterior inferior 3 rd Layer : 3 rd Layer : Erector spinae (Sacrospinalis) & Semispinalis. Erector spinae (Sacrospinalis) & Semispinalis. 4 th Layer : 4 th Layer : Number of small muscles called multivators, rotators, interspinalis, intertransverses & muscles forming the suboccipital triangle. Number of small muscles called multivators, rotators, interspinalis, intertransverses & muscles forming the suboccipital triangle.

5. Trapezius Origin: From Occipital bone (Medial 1/3 of superior nuchal line), external occipital protuberance, Ligamentum nuchae, spines of all cervical & all thoracic vertebrae and supraspinous ligament Origin: From Occipital bone (Medial 1/3 of superior nuchal line), external occipital protuberance, Ligamentum nuchae, spines of all cervical & all thoracic vertebrae and supraspinous ligament Insertion : posterior border of lateral 1/3 of the clavicle, medial margin of acromion upper lip of the crest of the spine of the clavicle. Insertion : posterior border of lateral 1/3 of the clavicle, medial margin of acromion upper lip of the crest of the spine of the clavicle.

6. Nerve supply: Spinal accessory cranial nerve & C 3,4 Nerve supply: Spinal accessory cranial nerve & C 3,4 Actions: Actions: upper fibers: elevate the shoulder upper fibers: elevate the shoulder Lower fibers: depress the shoulder. Lower fibers: depress the shoulder. Middle fibers: brace back (retraction) of shoulder Middle fibers: brace back (retraction) of shoulder It also, helps in raising the arm above 90° with (serratus anterior). It also, helps in raising the arm above 90° with (serratus anterior).

7. Latissimus Dorsi Origin: Origin: 1- Lower 6 thoracic spine. 1- Lower 6 thoracic spine. 2- Thoracolumbar fascia. 2- Thoracolumbar fascia. 3- Iliac crest. 3- Iliac crest. 4- Lower 3 or 4 ribs. 4- Lower 3 or 4 ribs. 5- Back of the inferior angle of the scapula. 5- Back of the inferior angle of the scapula. Insertion: floor of the bicipital groove. Insertion: floor of the bicipital groove. Nerve supply: Nerve to Latissimus dorsi (thoracodorsal nerve). Nerve supply: Nerve to Latissimus dorsi (thoracodorsal nerve). Action: adduction, medial rotation. Action: adduction, medial rotation. It also helps in extension and climbing. It also helps in extension and climbing.

9. 1 st layer: 1 st layer: Trapezius Trapezius Latissimus dorsi Latissimus dorsi 2 nd layer: 2 nd layer: Levator scapulae Levator scapulae Rhomboid minor Rhomboid minor Rhomboid major. Rhomboid major.

10. Levator scapulae Levator scapulae Origin: Transverse processes of upper 4 cervical vertebrae. Origin: Transverse processes of upper 4 cervical vertebrae. Insertion: Medial border of scapula. Insertion: Medial border of scapula. Nerve supply: C3,4 & 5 Nerve supply: C3,4 & 5 Action: Elevate the medial border of the scapula. Action: Elevate the medial border of the scapula. Rhomboid minor Rhomboid minor Origin: Ligamentum nuchae & spines of C 7& T1 Origin: Ligamentum nuchae & spines of C 7& T1 Insertion: Medial border of the scapula. Insertion: Medial border of the scapula. Nerve supply: C4& 5 Nerve supply: C4& 5 Action: Raises the medial border of scapula upward & medially. Action: Raises the medial border of scapula upward & medially.

12. Rhomboid Major Rhomboid Major Origin: Spines of T2,3,4 & 5. Origin: Spines of T2,3,4 & 5. Insertion: Medial border of scapula. Insertion: Medial border of scapula. Nerve supply: C4 & 5. Nerve supply: C4 & 5. Action: Raises the medial border of the scapula upward and medially. Action: Raises the medial border of the scapula upward and medially.

15. Origin: Origin: 1- Lower 6 thoracic spine, 1- Lower 6 thoracic spine, 2- Thoracolumbar fascia, 2- Thoracolumbar fascia, 3- Iliac crest 3- Iliac crest 4- Lower 3 or 4 ribs and 4- Lower 3 or 4 ribs and 5- Back of the inferior angle of the scapula 5- Back of the inferior angle of the scapula Insertion: Insertion: floor of the bicipital groove floor of the bicipital groove

16. Deltoid

18. Muscles connecting scapula to the Humerus

20. Supraspinatus Supraspinatus Origin: supraspinous fossa. Insertion: top of greater tubercle. Nerve: Suprascapular N. Action: Starts abduction from 0 to 15. 0 to 15. Steadies head of humerus. Steadies head of humerus. Infraspinatus Infraspinatus Origin: infraspinous fossa Insertin: middle impression of greater tubercle. Nerve: Suprascapular nerve. Action: adduction & Steadies head of humerus

22. Teres minor Origin: Upper 2/3 of lateral border of scapula Origin: Upper 2/3 of lateral border of scapula Insertion: lower impression of the greater tubercle. Insertion: lower impression of the greater tubercle. Nerve Axillary Nerve Axillary Action: adduction & Lateral rotation. Action: adduction & Lateral rotation. Teres Major Teres Major Origin: lower 1/3 of lateral border of scapula. Origin: lower 1/3 of lateral border of scapula. Insertion: Medial lip of intertubercular groove Insertion: Medial lip of intertubercular groove Nerve: lower subscapular n. Nerve: lower subscapular n. Action: Adduction, medial rotation and extension. Action: Adduction, medial rotation and extension.

23. Subscapularis Subscapularis Origin: Subscapular fossa Insertion: Lesser tubercle (tuberosity) of Humerus. Nerve: Upper & lower subscapular nerve. Action: adduction & medial rotation of shoulder. The tendons of Suprasinatus, & infraspinatus, & teres minor, and subscapularis form rotator-cuff. form rotator-cuff.

24. Rotator cuff: Rotator cuff: 1-Supraspinatus. 1-Supraspinatus. 2- infraspinatus 2- infraspinatus 3- Teres minor. 3- Teres minor. 4- Subscapularis 4- Subscapularis