Module I- The Back (Musculature, Nerves & Arteries)

Cadaver Lab Module I, Sources: Class contents, MedCharts Anatomy by Thomas R. Gest et al.

Label the figure

1. External occipital protuberance

2. Nuchal ligament

3. Spinous process of T1 vertebra

4. Supraspinous ligament

5. Anterior longitudinal ligament

What is the purpose of the supraspinous ligament?

The supraspinous ligament connects to the spinous process and the external occipital protuberance. This ligament thickens in the cervical region and is called the nuchal ligament.

Define thoracolumbar fascia

A diamond shaped band of connective tissue that serves as an attachment for various muscles.

Name the bony landmarks to which thoracolumbar fascia is anchored

• median sacral crest

• the iliac crest

• the lumbar, spinous, and transverses processes

Name the muscle!

Trapezius

Origin, insertion, innervation & artery of the trapezius muscle

• Origin: Medial third of the superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous processes of vertebrae C7–T12

• Insertion: Lateral third of the clavicle, medial side of the acromion and the upper crest of the scapular spine, tubercle of the scapular spine

• Innervation: Motor: spinal accessory (XI); Proprioception: C3–C4

• Artery: Transverse cervical a.

Name the muscle!

Deltoid

Origin, insertion, innervation & arteries of the deltoid muscle

• Origin: Lateral one-third of the clavicle, acromion, the lower lip of the crest of the spine of the scapula

• Insertion: Deltoid tuberosity of the humerus

• Innervation: Axillary nerve (C5,6) from the posterior cord of the brachial plexus

• Artery: Posterior circumflex humeral a.

Name the muscle!

Latissimus dorsi

Origin, insertion, innervation & arteries of the latissimus dorsi muscle

• Origin: Vertebral spines from T7 to the sacrum, posterior third of the iliac crest, lower 3 or 4 ribs, sometimes from the inferior angle of the scapula

• Insertion: Floor of the intertubercular groove

• Innervation: Thoracodorsal nerve (C7,8) from the posterior cord of the brachial plexus

• Artery: Thoracodorsal a

Name the muscle!

Levator scapulae

Origin, insertion, innervation & arteries of the levator scapulae muscle

• Origin: Transverse processes of C1–C4 vertebrae

• Insertion: Medial border of the scapula from the superior angle to the spine

• Innervation: Dorsal scapular nerve (C5); upper part of the muscle receives branches of C3 & C4

• Artery: Dorsal scapular a.

Name the muscle!

Rhomboideus minor

Origin, insertion, innervation & arteries of the rhomboideus minor muscle

• Origin: Inferior end of the ligamentum nuchae, spines of vertebrae C7 and T1

• Insertion: Medial border of the scapula at the root of the spine of the scapula

• Innervation: Dorsal scapular nerve (C5)

• Artery: Dorsal scapular a.

Name the muscle!

Rhomboideus major

Origin, insertion, innervation & arteries of the rhomboideus minor muscle

• Origin: Spines of vertebrae T2–T5

• Insertion: Medial border of the scapula inferior to the spine of the scapula

• Innervation: Dorsal scapular nerve (C5)

• Artery: Dorsal scapular a.

Name the muscle!

Supraspinatus

Origin, insertion, innervation & arteries of the supraspinatus muscle

• Origin: Supraspinatous fossa

• Insertion: Greater tubercle of the humerus (highest facet)

• Innervation: Suprascapular nerve (C5,6) from the superior trunk of the brachial plexus

• Artery: Suprascapular a.

Name the muscle!

Infraspinatus

Origin, insertion, innervation & arteries of the infraspinatus muscle

• Origin: Infraspinatous fossa

• Insertion: Greater tubercle of the humerus (middle facet)

• Innervation: Suprascapular nerve

• Artery: Suprascapular a.

Name the muscle!

Subscapularis

Origin, insertion, innervation & arteries of the subscapularis muscle

• Origin: Medial two-thirds of the costal surface of the scapula (subscapular fossa)

• Insertion: Lesser tubercle of the humerus

• Innervation: Upper and lower subscapular nerves (C5,6)

• Artery: Subscapular a.

Name the muscle!

Serratus posterior superior

Origin, insertion, innervation & arteries of the serratus posterior superior muscle

• Origin: Ligamentum nuchae, spines of vertebrae C7 and T1–T3

• Insertion: Ribs 1–4, lateral to the angles

• Innervation: Branches of the ventral primary rami of spinal nerves T1–T4

• Artery: Posterior intercostal aa. 1–4

Name the muscle!

Serratus posterior inferior

Origin, insertion, innervation & arteries of the serratus posterior inferior muscle

• Origin: Thoracolumbar fascia, spines of vertebrae T11–T12 and L1–L2

• Insertion: Ribs 9–12, lateral to the angles

• Innervation: Branches of the ventral primary rami of spinal nerves T9–T12

• Artery: Lowest posterior intercostal a., subcostal a., first two lumbar aa.

Name the muscle!

Teres minor

Origin, insertion, innervation & arteries of the teres minor muscle

• Origin: Upper 2/3 of the lateral border of the scapula

• Insertion: Greater tubercle of the humerus (lowest facet)

• Innervation: Axillary nerve (C5,6) from the posterior cord of the brachial plexus

• Artery: Circumflex scapular a.

Name the muscle!

Teres major

Origin, insertion, innervation & arteries of the teres major muscle

• Origin: Dorsal surface of the inferior angle of the scapula

• Insertion: Crest of the lesser tubercle of the humerus

• Innervation: Lower subscapular nerve (C5,6) from the posterior cord of the brachial plexus

• Artery: Circumflex scapular a.

Name the muscle!

Spinalis

Origin, insertion, innervation & arteries of the spinalis muscle

• Origin: Spinous processes at inferior vertebral levels

• Insertion: Spinous processes at superior vertebral levels and base of the skull

• Innervation: Dorsal primary rami of spinal nerves C2–L3

• Artery: Supplied segmentally by deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa.

Name the muscle!

Longissimus

Origin, insertion, innervation & arteries of the longissimus muscle

• Origin: Transverse process at inferior vertebral levels

• Insertion: Transverse process at superior vertebral levels and mastoid process

• Innervation: Dorsal primary rami of spinal nerves C1–S1

• Artery: Supplied segmentally by deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa.

Name the muscle!

Iliocostalis

Origin, insertion, innervation & arteries of the iliocostalis muscle

• Origin: Iliac crest and sacrum

• Insertion: Angles of the ribs

• Innervation: Dorsal primary rami of spinal nerves C4–S5

• Artery: Supplied segmentally by deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa.

Name the muscle!

Splenius capitis

Origin, insertion, innervation & arteries of the splenius capitis muscle

• Origin: Ligamentum nuchae and spinous processes of C4–T6 vertebrae

• Insertion: Mastoid process and lateral end of the superior nuchal line

• Innervation: Dorsal primary rami of spinal nerves C2–C6

• Artery: Supplied segmentally by deep cervical a., posterior intercostal aa.

Name the muscle!

Splenius cervicis

Origin, insertion, innervation & arteries of the Splenius cervicis muscle

• Origin: Spinous processes of T3–T6 vertebrae

• Insertion: Transverse processes (posterior tubercles) of C1–C3 vertebrae

• Innervation: Dorsal primary rami of spinal nerves C2–C6

• Artery: Supplied segmentally by deep cervical a., posterior intercostal aa.

Name the muscle!

Semispinalis

Origin, insertion, innervation & arteries of the semispinalis muscle

• Origin: Transverse processes of C7–T12

• Insertion: Capitis: back of skull between nuchal lines; Cervicis & Thoracis: spines 4–6 vertebrae above origin

• Innervation: Dorsal primary rami of spinal nerves C1–T12

• Artery: Supplied segmentally by deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa.

Name the muscle!

Rectus capitis posterior minor

Origin, insertion, innervation & arteries of the Rectus capitis posterior minor muscle

• Origin: Posterior tubercle of atlas

• Insertion: Inferior nuchal line medially

• Innervation: Suboccipital nerve (DPR of C1)

• Artery: Occipital a

Name the muscle!

Rectus capitis posterior major

Origin, insertion, innervation & arteries of the Rectus capitis posterior major muscle

• Origin: Spinous process of axis

• Insertion: Inferior nuchal line

• Innervation: Suboccipital nerve (DPR of C1)

• Artery: Occipital a.

Name the muscle!

Obliquus capitis superior

Origin, insertion, innervation & arteries of the obliquus capitis superior muscle

• Origin: Transverse process of atlas

• Insertion: Occipital bone above inferior nuchal line

• Innervation: Suboccipital nerve (DPR of C1)

• Artery: Occipital a.

Name the muscle!

Obliquus capitis inferior

Origin, insertion, innervation & arteries of the obliquus capitis inferior muscle

• Origin: Spinous process of the axis

• Insertion: Transverse process of atlas

• Innervation: Suboccipital nerve (DPR of C1)

• Artery: Occipital a.

Name the muscle!

Multifidus

Origin, insertion, innervation & arteries of the multifidus muscle

• Origin: Sacrum, transverse processes of C3–L5

• Insertion: Spinous processes 2–4 vertebral levels superior to their origin

• Innervation: Dorsal primary rami of spinal nerves C1–L5

• Artery: Supplied segmentally by deep cervical a., posterior intercostal aa., subcostal aa., lumbar aa.