Back & Shoulder Region

Ernest F. Talarico, Jr., Ph.D.Associate Director of Medical EducationAssociate Professor of Anatomy & Cell BiologyCourse Director, Human Gross Anatomy & EmbryologyIndiana University School of Medicine – NorthwestGary, Indiana AY14-15

Human Gross Anatomy

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Objectives

Identify all structures in this region

Understand anatomical relationships in this region

To be able to comprehend and discuss the structure of the nervous system

To apply this knowledge to clinical situations and radiography

The BackHuman Gross Anatomy

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Vertebral Column(Spine)

• 33 vertebrae– 7 cervical (C)

– 12 thoracic (T)

– 5 lumbar (L)

– 5 sacral (S)

– 4 coccygeal (C0)

cervical

thoracic

lumbar

sacral

coccygeal

Intervertebral disc

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Vertebrae (vertebra = singular)

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Vertebrae (vertebra = singular)

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Nervous System

• Somatic Motor– general somatic efferent

(GSE)

– single target organ

– no synapse

– fast - myelin

• Visceral Motor– general visceral efferent

– 2 to 3 target organs

– 2 neuron relay from CNS

– slow - myelin

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Spinal Nerves (31 pairs)

• all are mixed nerves (sensory and motor)

• 4 fiber components– Sensory

• GSA: general somatic afferent

• GVA: general visceral afferent

– Motor

• GSE: skeletal

• GVE: visceral

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Typical Thoracic

Spinal Nerve

31 pairs of spinal nerves:

8 cervical

12 thoracic

5 lumbar

5 sacral

1 coccygeal

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Muscles of the BackSuperficial

GroupIntermediate

GroupDeep Group

trapezius m.

latissiumus dorsi m.

rhomboideus major m.

rhomboideus minor m.

levator scapulae m.

serratus posterior superior m.

serratus posterior inferior m.

Splenius (capitius; cervicis)

Semispinalis m.

Erector Spinae iliocostalis m.

longissimus m.spinalis m.

anchor the upper limb to the axial skeleton

function in respiration intrinsic muscles of the dorsum (supplied by dorsal nerve rami)

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Muscles of the BackSuperficial Group

trapezius m.

latissiumus dorsi m.

rhomboideus major m.

rhomboideus minor m.

levator scapulae m.

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Muscles of the BackIntermediate Group

serratus posterior superior m.

serratus posterior inferior m.

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Muscles of the BackDeep Group

Splenius (capitius; cervicis)

Semispinalis m. (5, 13)

Erector Spinae iliocostalis m. (11)

longissimus m. (10)spinalis m. (18)

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Muscles of the BackDeep Group – Other intrinsic muscles

Rotatores m. (14)

Intertransverse mm. (16)

[note: levators costarum mm.;

13)

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Spinal Cord

• Meninges– Pia mater

• denticulate ligaments

• filum terminale

– Arachnoid mater (9)

• subarachnoid space with CSF

• Lumbar cistern (L1 – S2)

– Dura mater (8)

• Epidural space

• Subdural space

Table #1 sacral region

Table #2 lower cervical

Table #3 U - thoracic region

Table #4 L - thoracic region

Table #5 lumbar region

Table #6 sacral region

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L1/L2 (adult)

L2/L3 (child)

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CSF & DIAGNOSIS OF NEUROLOGICAL DISORERS

• lumbar puncture (L3/L4; L4/L5)

• myelography and intrathecal route for medications

• need prior CT Scan to rule out ICP

Sample Collection (7 – 8 ml)

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Diagnostic Analysis• Cell Count WBCs or RBCs make CSF turbid

bacterial meningitis (mostly neutrophils)

meningeal syphilis & fungal infections (lymphocytes)

RBCs subarachnoid hemorrhage or AV malformation

traumatic tap vs. subarachnoid hemorrhage

ictus xanthochromia (faint yellow color)

Differential Protein• 200 mg/100 ml gives CSF a yellow-orange color

protein is due to vascular endothelial cell permeability (BBB breakdown)

• pathological conditions (hemorrhage, syphilis, meningitis, MS, Guillian-Barré Syndrome, diabetic neuropathy)

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Differential Glucose• Glucose concentration is in bacterial infections

Microorganisms

CSF Pressure• decreased dehydration; CSF leaks

spinal subarachnoid block

• increased brain edema; intracranial mass

acute stroke; infections, etc.

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Suboccipital Region• Reflect trapezius; splenius

and semispinalis

• Identify– Rectus capitis minor m. (16)– Rectus capitis major m. (18)– Superior oblique m. (17)– Inferior oblique m. (19)

• Identify– Greater occipital n. (C2; 6)– Suboccipital n. (C1; 5)– Occipital artery (2)– Vertebral artery

The ShoulderHuman Gross Anatomy

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Muscles of the Shoulder Region

• Deltoid (axillary n.)

• Suprapinatus (suprascapular n.)

• Infraspinatus (suprascapular n.)

• Subscapularis (upper & lower subscapular nn.)

• Teres major (lower subscapular n.)

• Teres minor (axillary n.

• Latissimus dorsi (thoracodorsal n.)

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• Quadrangular space– Boundaries

• Teres minor (4) & subcapularis

• Teres major (6)

• Long head of triceps

• surgical neck of humerus (laterally)

– Contents (9)

• Axillary nerve

• Posterior humeral circumflex artery

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• Triangular space– Boundaries

• Teres major (6)

• Long head of triceps (10)

• Teres minor (4)

– Contents

• Circumflex scapular artery & vein (5)

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• Triangular Interval– Boundaries

• Teres major (6)

• Long head of triceps (10)

• Medial head of triceps (or humerus)

– Contents

• Radial nerve (21)

• Profunda brachii artery (20)

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• Triangle of Auscultation

– Boundaries

• Trapezius m.

• Latissimus dorsi m.

• Scapula

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Nerves Arteries

Suprascapular n. (C5 – C6)

Dorsal scapular n.

Suprascapular a.

Dorsal scapular a.

Anastomoses around the scapula

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The Shoulder Joint1) Cut and reflect the

coracobrachialis m., the short head of biceps brachii m., and the long head of triceps brachii

2) Clean the insertion of subscapularis

3) Identify the fibrous capsule and remove the posterior portion

4) Attempt opening up the joint (removal of the head of the humerus may be necessary