Musculoskeletal System - The Back Anatomy Flashcards

Vocabulary flashcards covering the anatomical structures, innervations, blood supplies, functions, and clinical spaces of the back based on the lecture material.

Extrinsic Back Muscles

Back muscles located superficial to the thoracolumbar fascia that are innervated by anterior (ventral) rami of spinal nerves (or cranial nerve XI) and primarily move the upper limbs and ribs.

Intrinsic Back Muscles

Deep back muscles enclosed by the thoracolumbar fascia that are innervated by posterior (dorsal) rami of spinal nerves and function to move the vertebral column and maintain upright posture.

Trapezius Muscle

A superficial extrinsic back muscle innervated by the spinal accessory nerve (CN XI) for motor function and C3-C4 spinal nerves for proprioception; it elevates, adducts, depresses, and rotates the scapula.

Latissimus Dorsi Muscle

A large superficial extrinsic back muscle innervated by the thoracodorsal nerve (C6-C8) that extends, adducts, and medially rotates the humerus.

Levator Scapulae Muscle

A second-layer superficial extrinsic back muscle innervated by C3, C4 spinal nerves and the dorsal scapular nerve that functions to elevate the scapula.

Rhomboid Major Muscle

A superficial extrinsic back muscle innervated by the dorsal scapular nerve (C4-C5) that retracts (adducts) and elevates the scapula.

Rhomboid Minor Muscle

A superficial extrinsic back muscle located superior to rhomboid major, innervated by the dorsal scapular nerve (C4-C5), that retracts (adducts) and elevates the scapula.

Serratus Posterior Superior Muscle

An intermediate extrinsic back muscle innervated by the anterior rami of upper thoracic (intercostal) nerves T2-T5 that elevates ribs II to V.

Serratus Posterior Inferior Muscle

An intermediate extrinsic back muscle innervated by the anterior rami of lower thoracic (intercostal) nerves T9-T12 that depresses ribs IX to XII.

Supraspinatus Muscle

A rotator cuff muscle innervated by the suprascapular nerve (C5 and C6) that initiates abduction of the humerus to 15 degrees at the glenohumeral joint.

Infraspinatus Muscle

A rotator cuff muscle innervated by the suprascapular nerve (C5 and C6) that produces lateral rotation of the arm at the shoulder joint.

Teres Minor Muscle

A rotator cuff muscle innervated by the axillary nerve that produces lateral rotation of the arm at the shoulder joint.

Teres Major Muscle

A scapular muscle innervated by the lower subscapular nerve that medially rotates and extends the arm at the glenohumeral joint.

Splenius Muscles

Intrinsic back muscles (splenius capitis and splenius cervicis) innervated by posterior rami of cervical spinal nerves; bilateral contraction extends the head and neck, while unilateral contraction causes ipsilateral lateral flexion and rotation.

Erector Spinae Muscle Group

The primary extensors of the vertebral column divided into iliocostalis, longissimus, and spinalis; bilateral contraction extends the trunk, while unilateral contraction causes ipsilateral lateral flexion.

Transversospinalis Group

A deep layer of intrinsic back muscles consisting of semispinalis, multifidus, and rotatores running obliquely from transverse processes to spinous processes to assist in extension, rotation, and stabilization of the vertebral column.

Thoracolumbar Fascia

A deep investing membrane in the posterior thorax and abdomen consisting of anterior, middle, and posterior layers that encloses the intrinsic (paravertebral) muscles of the back.

Triangle of Auscultation

An anatomical landmark bounded inferiorly by the superior border of latissimus dorsi, medially by the lateral border of trapezius, and laterally by the medial border of the scapula; used for pulmonary auscultation.

Triangle of Petit

Also called the inferior lumbar triangle, a space bounded inferiorly by the iliac crest, posteriorly by the latissimus dorsi, and anteriorly by the external oblique, serving as a site for lumbar hernias.

Cutaneous Innervation of the Back

Sensation to the skin of the back provided by the posterior (dorsal) rami of spinal nerves.

Lymphatic Drainage of the Back Skin

Drainage route where lymph from the back skin of the neck enters occipital, deep cervical, and axillary nodes, while lymph from the trunk skin drains into axillary nodes and superficial inguinal nodes.