Relearning Human Anatomy

How many sections make up the Vertebral Column

5 sections

What are the sections that make up the Vertebral Column

• Cervical

• Thoracic

• Lumbar

• Sacral

• Coccyx

Primary Functions of Vertebral Column

The 33 vertebrae function together to aid movement and posture as well as providing support and protection of the Spinal Cord.

Vertebral Foramen

The hole created by the load-bearing vertebral body & vertebral arch. When aligned they create a channel to protect and enclose the spinal cord. 

Vertebral Arch

Has multiple features which act as articulation for other bones or attachment sites for ligaments & muscles.

• spinous processes

• transverse processes

• pedicles

• lamina

Intervertebral disc

Allow for shock absorption and movement

Ligaments that articulate with the Bones of the Back

• ligamentum flavum

• interspinous ligament

• supraspinous ligament

• intertransverse ligaments

• anterior & posterior longitudinal ligaments

Muscles of the Back

Can be arranged into 3 categories based on location:

• Superficial

• Intermediate

• Intrinsic

Superficial back muscles

• found just under the skin

• Allows movement of the shoulder

• latissimus dorsi, trapezius, levator scapulae and the rhomboids

Intermediate back muscles

• Work to elevate and depress the rib cage

• Serratus posterior superior

• serratus posterior inferior

Intrinsic back muscles

Help movements of the vertebral column & control posture

Trapezius Origin:

• Bottom of the skull

• ligamentum nuchae

• spinous processes of C7-T12

Trapezius Insertion

• Clavicle

• Acromion

• Scapula spine

Trapezius Innervation

• Motor innervation from accessory nerve

• Receives propriorecptor fibres from C3+C4 spinal nerves

Trapezius Action

• The upper fibres of the trap elevates the scapula + rotates scapula during abduction of the arm

• The middle fibres retract the scapula

• The lower fibres pull the scapula inferiorly 

Trapezius

A broad flat triangular muscle. Most superficial of all back muscles

Latissimus Dorsi

This muscle originates from the lower part of the back, where it covers a wide area

Latissimus Dorsi Origin

• Spinous processes of T6-T12

• Thoracolumbar fascia

• Iliac crest

• inferior 3 ribs

Latissimus Dorsi Insertion

• The fibres converge into a tendon that attaches to intertubercular sulcus of the humerus

Latissimus Dorsi Innervation

• Thoracodorsal Nerve

Latissimus Dorsi Action

• Extends upper limb

• Adducts upper limb

• medially rotates the upper limb

Levator Scapulae

A small strap-like muscle. It begins at the neck and descends to attach to the scapula

Levator Scapulae Origin

Transverse processes of C1-C4 vertebrae

Levator Scapulae Insertion

Medial border of the scapula

Levator Scapulae Innervation

Dorsal scapular nerve

Levator Scapulae Action

Elevates the scapula

Rhomboid Major Origin

Spinous processes of T2-T5 vertebrae

Rhomboid Minor Origin

Spinous processes of C7-T1 vertebrae

Rhomboid Major Insertion

Medial border of scapula (between scapula spine + inferior angle)

Rhomboid Minor Insertion

Medial border of the scapula, at the level of the spine of the scapula

Rhomboid Major + Minor Innervation

Dorsal scapular nerve

Rhomboid Major + Minor Action

• Retract the scapula

• Rotate the scapula

Serratus Posterior Superior

This muscle is a thin, rectangular shaped muscle. It lies deep to the rhomboid muscles on the upper back

Serratus Posterior Superior Origin

• Lower portion of ligamentum nuchae

• Cervical + thoracic spines C7-T3

Serratus Posterior Superior Insertion

• Ribs 2-5

Serratus Posterior Superior Action

Elevates ribs 2-5

Serratus Posterior Superior Innervation

Intercostal nerves

Serratus Posterior Inferior Origin

Thoracic + Lumbar spines (T11-L3)

Serratus Posterior Inferior Insertion

Ribs 9-12

Serratus Posterior Inferior Action

Depress ribs 9-12

Serratus Posterior Inferior Innervation

Intercostal nerves

Semispinalis Capitis Origin

Transverse processes of C4-T10

Semispinalis Capitis Insertion

• Spinous processes of C2-T4

• Occipital bone of the skull

Semispinalis Capitis Innervation

Posterior rami of the spinal nerves

Semispinalis Capitis Actions

• Extend the hed

• Contralaterally rotates the head

• Contralaterally rotates the vertebral column

Semispinalis Capitis

The most superficial of the deep intrinsic muscles. It can be divided by its superior attachments into thoracic, cervicis, and capitis

Multifidus

Located underneath the semispinalis muscle. It is most developed in the lumbar area

Multifidus Origin

• Sacrum

• Posterior iliac spine

• erector spinae

• mamillary processes of lumbar vertebrae

• transverse processes of T1-T3

• Articular processes of C4-C7

Multifidus Inse

Vertebral spinous processes

Multifidus Innervation

Posterior rami of the spinal nerves

Multifidus Action

Stabilizes the vertebral column

Rotatores

The deepest muscles of the transversospinales group. They are the most prominent in the thoracic region.

Rotatores Origin

Vertebral transverse processes

Rotatores Insertion

Lamina + spinous processes of the vertebrae above

Rotatores Action

• Extension of vertebral column

• rotation of vertebral column

• stabilizes the vertebrae

• Proprioceptive function

Rotatores Innervation

Posterior rami of the spinal nerves

Quadrangular Space

• The anatomical space located in the posterior axilla region

• Provides a conduit for structures to pass between the axilla and posterior compartment of the arm (axillary nerve)

• Borders:

  • Superior: inferior margin of teres minor

  • Lateral: surgical neck of the humerus

  • Medial: long head of triceps brachii

  • Inferior: superior aspect of teres major

Quadrangular Space Syndrome

• Refers to compression of the axillary nerve and posterior circumflex humeral artery as they pass through the space

• Thought to be caused by hypertrophy of the muscular borders of the space, or by the formation of fibrotic bands between muscles

• Clinically displays as pain and paraesthesia in the distribution of the axillary nerve as well as pain upon shoulder abduction and external rotation

Triangular interval

• An anatomical space located immediately below the axilla region

• allows structures to pass between anterior and posterior compartments of the upper arm (radial nerve)

• Boarders

  • Inferior: teres major

  • Lateral: shaft of humerus/lateral head of triceps brachii

  • Medial: lateral border of long head of the triceps brachii

Triangular interval syndrome

• Refers to compression of the radial nerve as it passes through the triangular interval

• Thought it can occur due to hypertrophy of triceps brachii or teres minor

• Clinically presents as neuropathic pain or paraesthesia in sensory distribution radial nerve, or weakness in extension of elbow, wrist, or digits

Triangular Space

• Refers to the anatomical space located in the axilla

• Allows structures to pass between the axilla and posterior scapular region (Circumflex scapular artery)

• Boarders:

  • Lateral: medial margin of the long head of the triceps brachii

  • Inferior: superior margin of the teres major

  • Superior: inferior border of the teres minor (or subscapularis)$

Axilla

• The area that lies underneath the glenohumeral joint at the junction of the upper limb and thorax

• Is a passageway by which neruovascular and muscular structures can enter and leave the upper limb

Axilla region borders

• Apex: axillary inlet (formed by lateral border of first rib, superior border of scapula, posterior border of clavicle)

• Lateral wall: formed by inter-tubercular groove of the humerus

• Anterior wall: contains the pectoralis major and the underlying pectoralis minor and subclavius muscles

• Medial wall: consists of the serratus anterior and the thoracic wall

• Posterior wall: formed by the subscapularis, teres major, and latissimus dorsi

Axillary region contents

• Axillary artery: the main artery supplying the upper limb

• Axillary vein: main vein draining from upper limb

• Brachial plexus: collection of spinal nerves that form peripheral nerves of upper limb

• Axillary lymph nodes: filters lymphatic fluid drained from upper limb

• Biceps brachii + coracobrachialis: these muscle tendons move through the axilla

Passageways Exiting the Axilla

• Inferiorly and laterally into the upper limb

• Through the quadrangular space (branch of axillary artery)

• Clavipectoral triangle (cephalic vein, medial + lateral pectoral nerves)$

Thoracic Outlet Syndrome

• compression of the vessels and nerves in the apex of the axilla region

• Common causes:

  • Trauma

  • Repetitive movements

  • Extra cervical rib

• Present as pain in affected limb, tingling, muscle weakness, and discoloration

Cubital fossa

• A triangular-shaped depression over the anterior aspect of the elbow joint

• Area of transition between arm and forearm

• Borders

  • Lateral: medial border of brachioradialis

  • Medial: lateral border of pronator teres

  • Superior: horizontal line drawn between epicondyles of humerus

  • Roof: bicipital aponeurosis, fascia, subcutaneuous fat, and skin

  • Floor: brachialis & supinator

Cubital fossa contents

• Radial nerve: travels along lateral border of cubital fossa (motor and sensory of posterior forearm & hand)

• Biceps tendon

• Brachial artery: bifurcates into the radial and ulnar arteries at apex

• Median nerve: passes through fossa passing between two heads of pronator teres (motor and sensory function anterior forearm & hand)

Supracondylar Fracture

• Fracture to the distal humerus

• Typically transverse or oblique most commonly caused by falling on an outstretched arm

• Can cause damage to the brachial artery or anterior interosseous nerve

Ulnar tunnel

• The fibro-osseous space located on the posteromedial aspect of the elbow

• Transmits the ulnar nerve from the arm into the forearm

Ulnar tunnel borders

• Medial: medial epicondyle of the humerus

• Lateral: olecranon of the ulna

• Floor: elbow joint capsule and medial collateral ligament of the elbow

• Roof: ligament spanning between the medial epicondyle and olecran

Cubital tunnel syndrome

• refers to compression of the ulnar nerve within the ulnar tunnel

• One of the most common peripheral neuropathy of the upper limb

• Patient experience altered sensation, loss of motor function (including weakness and wasting of intrinsic hand muscles), pain during elbow flexion.

Carpal Tunnel

• A narrow passageway found on anterior portion of the wrist

• Is the entrance to the palm for several tendons and the median nerve

Carpal Tunnel borders

• Deep carpal arch

• superficial flexor retinaculum

Carpal Arch

• concave on palmar side (forms base & sides of carpal tunnel)

• Scaphoid and trapezium tubercles (form lateral border)

• hook of the hamate and pisiform (form medial border)

Flexor retinaculum

• Thick connective tissue which forms the roof of the carpal tunnel

• Turns the carpal arch into the carpal tunnel by bridging space between medial and lateral parts of the arch

• spans between hook of the hamate and pisiform

Carpal tunnel contents

• flexor pollicis longus tendon

• four flexor digitorum profundus tendons

• four flexor digitorum superficialis tendons