Back and vertebral Column

Mid-vertebral line and Scapular line

Triangle of auscultation

Landmark that indicates the location of the vertebral spines

Vertebral Furrow

Erector spinae muscles lie on both sides.

It sits at the very bottom of your neck, just above the first thoracic vertebra (T1)

Vertebral of Prominence is the seventh cervical vertebra (C7) and is easily palpable.

Identify the major superficial back muscles:

Trapezius, levator scapulae, rhomboid major, rhomboid minor, and latissimus dorsi.

Trapezius- the most superficial muscle

Innervations and Action of Trapezius:

Innerverted by Spinal Accessory Nerve (CN XI)

Action: Elevates, retracts, depresses, and upwardly rotates scapula.

Innervation and action of levator scapule:

Innervated by: Dorsal Scapular Nerve (C5)

Action: Elevates scapula, downward rotation

Innervation and action of rhomboid major and minor

Innervation: Dorsal Scapular Nerve (C5)

Action: Retracts and elevates scapula, downward rotation.

Innervation and action of Latissimus Dorsi

Innervation: Thoracodorsal Nerve (C6-C8)

Action: Extends, adducts, and medially rotates humerus.

Explain how the superficial back muscles contribute to scapular movement and

upper limb function.

Muscle	Scapular Action	Upper Limb Function
Trapezius	Elevation, retraction, depression, upward rotation	Raises arm overhead
Levator Scapulae	Elevation, downward rotation	Stabilizes scapula
Rhomboid Major/Minor	Retraction, downward rotation	Pulling movements
Latissimus Dorsi	Assists depression	Extension, adduction, medial rotation of humerus

Elevation:  trapezius, levator scapulae, rhomboids assist

Depression: Trap, latissimus dorsi, pectoralis minor

Protraction or Abduction- serratus anterior, pectoralis minor assists

Retraction or adduction: rhomboid major, minor and trapezius

Upward rotation- trapezius, serratus anterior

Downward rotation- rhomboid major and minor, levator scapulae, pectoralis minor

Differentiate the actions of scapular elevation, depression, protraction, retraction,

and rotation.

• Elevation = shrug

• Depression = push down

• Protraction = punch

• Retraction = row

• Upward rotation = raise arm overhead

• Downward rotation = lower arm back to side

Deep Intrinsic muscle

Primarily act on vertebral column.

Commonly referred as: Intrinsic back muscles, epaxial muscles, paraspinal muscles (clinically)

Innervated by dorsal (posterior) rami of spinal nerve at each vertebral level.

Responsible for maintaining posture, in constant use during body movements

Types of intrinsic muscle (deep muscle)

Superficial: Splenius capitus and cervicis

Intermediate: erector spinae

Deep: transversospinalis, suboccipital muscles

Splenius Capitus and Cervicis Muscle

Located deep to levator scapulae and rhomboid muscles, and superficial to erector spinae muscles

Action

Bilateral contraction: extension of head and neck

unilateral contraction: lateral flexion and rotation of head and neck.

Innervation

Segmentally innervated by dorsal rami. (Dorsal (posterior) rami of spinal nerves)

Erector Spinae

Three separate muscles (from lateral to medial): iliocostalis, longissimus, and spinalis

Long muscles of the back, paraspinal muscles

Location

• Located in the deep (intrinsic) layer of the back

• Runs on both sides of the vertebral column

• Extends from the sacrum and iliac crest inferiorly to the skull superiorly

Action

Bilateral contraction: extension of the vertebral column and control of posture

unilateral contraction: lateral flexion of vertebral column.

Innervation

Segmentally innervated by dorsal rami.

Transversospinalis Muscle

Located deep to the erector spinae muscles.

From superficial to deep: semispinalis, multifidus, and rotatores

Attachment

Muscle fibers arise from a transverse process and ascend between one to six vertebral levels to attach to the spinous process of neighboring vertebrae.

Action

Stabilization

Bilateral contraction: extension of the vertebral column

unilateral contraction: rotation of vertebral column to the contralateral side of the contracting transversospinalis muscle.

Innervation

Segmentally innervated by dorsal rami.

Suboccipital Muscles

Located inferior to the occipital bone and deep to the semispinalis capitis muscle.

rectus capitis posterior major and minor and obliquus capitis superior and inferior.

Action

Mainly postural muscles

may contribute to extension and rotation of the head.

Innervation

Dorsal ramus of C1 spinal nerve (also known as the suboccipital nerve).

Identify the major groups of deep back muscles including splenius, erector spinae,

transversospinalis, and suboccipital muscles.

Deep back muscles are the true back muscles. They lie deep to the superficial back muscles and are responsible for posture, stabilization, and movement of the vertebral column and head. All are innervated by the dorsal (posterior) rami of spinal nerves (except the suboccipital group, which receives the dorsal ramus of C1).