ALL Muscles of the Neck, Back and Trunk: Origin, Insertion, Function(s) and Nerve

Platysma:

Respuesta: Origin: Fascia over deltoid and pectoralis major muscles Insertion: Mandible and skin of lower face Function: (2) 1. Depresses and draws lower lip inferiorly 2. Depresses of mandible @ tempo mandibular joint Nerve: Facial nerve (cranial nerve 7)

Sternocleidomastoid (SCM):

Respuesta: Origin: - Medial 1/3 of clavicle (clavicular head, wider) - Manubrium of sternum (sternal head, skinny) Insertion: - Mastoid process of temporal bone - Lateral ½ of the superior nuchal line of occipital bone Function: (8) 1. Extension of head @ atlanto-occipital joint 2. Extension of upper neck @ spinal joints (double chin) 3. Flexion of lower neck @ spinal joints 4. Lateral flexion of head @ atlanto-occipital joint 5. Lateral flexion of neck @ spinal joint 6. Contralateral rotation of head @ atlanto-axial joint 7. Contralateral rotation of neck @ spinal joint 8. Elevation of sternum and clavicle (during forced inhalation) Nerve: Spinal accessory nerve (cranial nerve 11)

Anterior scalene:

Respuesta: Origin: Transverse process of C3-C6 (typical CVs) Insertion: Scalene tubercle on the 1st rib Function: (4) 1. Flexion of neck @ spinal joint 2. Lateral flexion of neck @ spinal joint 3. Contralateral rotation of neck @ spinal joint 4. Elevation of 1st rib (during deep inhalation) @ sternocostal and costospinal joints Nerve: Ventral rami of cervical spinal nerves at the corresponding levels

Middle Scalene:

Respuesta: Origin: Transverse process of C2-C7 Insertion: First rib Function: (3) 1. Flexion of neck @ spinal joint 2. Lateral flexion of neck @ spinal joint 3. Elevation of 1st rib (during deep inhalation) @ sternocostal and costospinal joints Nerve: Ventral rami of cervical spinal nerves at the corresponding levels

Posterior scalene:

Respuesta: Origin: Transverse process of C5-C7 Insertion: 2nd rib Function: (2) 1. Lateral flexion of neck @ spinal joint 2. Elevation of 2nd rib (during deep inhalation) @ sternocostal and costospinal joints Nerve: Ventral rami of cervical spinal nerves at the corresponding levels

Upper trapezius:

Respuesta: Origin: (descending fibers) External occipital protuberance and the medial 1/3 of superior nuchal line of the occipital bone from the ligamentum nuchae, the spinous process of C7 Insertion: Lateral 1/3 of the clavicle; and acromion of scapula Function: (8) 1. Extension of head (upper) @ atlanto-occipital joint 2. Extension of neck (upper) @ spinal joint 3. Lateral flexion of head (upper) @ atlanto-occipital joint 4. Lateral flexion of neck (upper) @ spinal joint 5. Contralateral rotation of head (upper) @ atlanto-axial joints 6. Contralateral rotation of neck (upper) @ spinal joints 7. Elevation of scapula (upper) @ scapulocostal joints 8. Upward rotation of scapula (upper and lower) @ scapulocostal joint Nerve: Spinal accessory nerve (Cranial nerve 11)

Middle trapezius:

Respuesta: Origin: Spinous process of T1-T5 (runs up to acromion, not to spine of scapula) Insertion: Acromion and spine of scapula Function: (1) 1. Retraction (adduction) of scapula (mostly middle) @ scapulocostal joint Nerve: Spinal accessory nerve (Cranial nerve 11)

Lower trapezius:

Respuesta: Origin: (ascending fibers) Spinous process of T6-T12 (will be tendonous) Insertion: Tubercle at the root of spine of scapula Function: (2) 1. Upward rotation of scapula (upper and lower) @ scapulocostal joint 2. Depression of scapula (lower) @ scapulocostal joint Nerve: Spinal accessory nerve (Cranial nerve 11)

Latissimus dorsi:

Respuesta: Origin: 1. Spinous process T7-L5 2. Crest of ilium and sacrum 3. Ribs 9-12 (via thoracolumbar fascia) 4. Inferior angle of the scapula (usually) Insertion: Bottom of the intertubercular groove of the humerus Function: (5) 1. Extension of arm @ glenohumeral joint 2. Adduction of arm @ glenohumeral joint 3. Medial rotation of arm @ glenohumeral joint 4. Depression of scapula @ scapulocostal joint 5. Anterior tilt of pelvis @ lumbosacral joint Nerve: Thoracodorsal nerve

Rhomboids minor:

Respuesta: Origin: Spinous processes of C7 and T1 Insertion: Medial (vertebral) border of scapula superior to spine Function: (3) 1. Retraction (adduction) of scapula @ scapulocostal joint 2. Elevation of scapula @ scapulocostal joint 3. Downward rotation of scapula @ scapulocostal joint Nerve: Dorsal scapular nerve