Anatomy

Gross Anatomy, Embryology and Histology.

What are the roots of the brachial plexus?

C5, C6, C7, C8 and T1

Where are the ‘divisions’ of the brachial plexus located anatomically?

Posterior to the clavicle

How are the cords of the brachial plexus named?

They are named by their position relative to the axillary artery.

What nerve arises directly from the C5, C6 and C7 roots?

Long Thoracic nerve (innervates Serratus anterior).

Which nerve arises from the Superior Trunk(C5-C6)?

Suprascapular nerve(innervates Supraspinatus and Infraspinatus)

Which nerve branches off the Posterior Cord?

Upper and Lower subscapular, Thoracodorsal, Radial and Axillary nerves.

(ULTRA mnemonic)

A patient presents with ‘Waiter’s Tip’ deformity. What is the injury?

Erb-Duchenne Palsy. Damage to the Upper Trunk (C5-C6). Results in loss of abduction, lateral rotation, and supination.

A ‘claw hand’ deformity involving all fingers suggests damage to which part of the plexus?

Klumpke Palsy. Damage to the Lower Trunk (C8-T1).

Winging of the scapula indicates damage to which nerve?

Long thoracic nerve.

Which nerve is most at risk during a mid-shaft humeral fracture?

Radial nerve (travels in the spiral groove)

Which nerve is most at risk in a surgical neck of the humerus fracture?

Axillary nerve.

Which muscles are supplied by the Musculocutaneous nerve?

Biceps brachii, Brachialis and Coracobrachialis (BBC muscles).

What is the sensory distribution of the Axillary nerve?

The Regimental Badge area over the lower half of the deltoid muscle.

The Median nerve supplies all the muscles in the anterior forearm EXCEPT which ones?

Flexor carpi ulnaris and the medial half of Flexor digitorum profundus (supplied by ulnar nerve).

Which nerve is responsible for thumb adduction?

Ulnar nerve (via the Adductor

Which nerves arise from the medial cord of brachial plexus?

Medial pectoral nerve, Medial cutaneous nerve of arm, Medial cutaneous nerve of forearm, Medial root of Median nerve and Ulnar nerve. (M4U mnemonic).

What does thoracodorsal nerve (C6-C8) innervate?

Latissimus Dorsi

Which nerve supplies the Rhomboids and Levator scapulae?

Dorsal scapular nerve (C5).

Loss of sensation in the medial 1.5 fingers and wasting of the hypothenar eminence indicates?

Ulnar nerve injury

Which nerve is compressed in carpal tunnel syndrome?

Median nerve

Where are the kidneys located?

Retroperitoneally, between T12-L3 vertebrae. Right kidney sits slightly lower than left (displaced by the liver).

What are the dimensions and weight of a typical adult kidney?

~10cm long, 5 cm wide, 5.5cm thick and weighs about …..

What structures make up the renal hilium?

Renal Vein, Renal artery and renal pelvis(and lymphatic/nerves). [Order from anterior to posterior, VAP]

Name the three layers of renal fascia from inside out.

1. Fibrous capsule (true capsule)
2. Perinephric fat (perirenal fat)
3. Renal (Gerota's) fascia
4. Paranephric fat (outermost)

At what vertebral level do the renal vessels arise?

The IV disc between L1 and L2.

What is the nerve supply of the kidney?

Renal plexus

Origin of the superior suprarenal artery?

Inferior phrenic artery

Origin of the middle suprarenal artery?

Abdominal aorta

Origin of the inferior suprarenal artery?

Renal artery

Outline the structures that traverse the major diaphragmatic openings

Inferior Vena Cava (T8), Eosophagus (T10) and Aorta (T12). (I 8 10 Eggs At 12)

How many lobes has each lung?

Right Lung-(3 lobes); Left Lung-(2 lobes)

Name the space divisions of the thoracic cavity

Right pleural cavity, Left pleural cavity and Mediastinum

List the constituents of the thoracic wall

List the constituents of the thoracic skeleton

1. Ribs (12 pairs)

2. Thoracic vertebrae (12) and intervetebral discs

3. Costal Cartilages

4. Sternum

What are the types of ribs?

True(1st to 7th), False(8th, 9th and usually 10th) and Floating ribs(sometimes 10th, 11th and 12th)

Classify Ribs

Typical and Atypical ribs

What is the shape of the thoracic cage?

Dome-shaped

True ribs are also called?

Vertebrosternal ribs

False ribs are also called?

Vetebrochondral ribs

What are true ribs?

True ribs(1st - 7th) attach directly to the sternum through their own costal cartilages.

What are false ribs?

False ribs(8th, 9th & 10th) are indirectly connected to the sternum as their cartilages are connected to the cartilage of the rib above them.

What are floating ribs?

The cartilages of Floating ribs(10th, 11th and 12th) do not connect with the sternum at all, instead they end in posterior abdominal musculature

Describe the components of a true rib.

• Head: Wedge-shaped head with two articular facets(for articulation with numerically corresponding and vertebra above)

• Neck: Connects head to body

• Tubercle: Smooth articular part for articulation with corresponding vertebra and rough non-articular part for attachment of costotranverse ligament

• Body: Thin, flattened and curved. Costal angle marks the point where the rib turns anterolaterally. Costal angle marks the lateral limit of deep back muscles attachment. Concave internal surface. Costal groove protects the intercostal vessels and nerve.

Explain the structure and significance of the body of a rib.

The rib body is thin, flat, and curved. At the costal angle, it changes direction and marks the lateral limit of deep back muscle attachment. The inferior internal surface has a costal groove that protects the intercostal vein, artery, and nerve (VAN).

What is the costal angle?

The costal angle is the point on a rib where it bends sharply, marking the transition from posterior to anterolateral direction and forming the lateral limit of deep back muscle attachment.

Describe the anatomy of the first rib

It is the broadest, shortest and most curved of all the ribs. It has only one articulatory facet on its head and has two transversely directed grooves on its superior surface for the passage of the subclavian vessels. A ridge and tubercule exists between the grooves called scalene tubercle/ridge, which provided attachment for the anterior scalene muscle

What makes the 2nd rib an atypical rib?

The presence of a tuberosity on its upper surface for the attachment of serratus anterior

What is the main atypical feature of the 10th rib?

The presence of only one articulatory surface on its head

What are the atypical features of the 11th and 12th ribs?

Presence of one articulatory facet on the head. They are short, and lack neck or tubercule

How are the intercoastal spaces named?

According to the name/number or the rib above them. (Hence, 11 intercostal spaces)

The space beneath the 12th rib is referred to as?

Subcostal space

Where are intercostal spaces widest?

Anterolaterally

Characteristic features of thoracic vertebrae?

• Bilateral costal facets on body of vertebrae(articulation with head of ribs)

• Costal facets on the transverse processes(articulation with tubercle of ribs)

• long spinous process

• Articular facets(articulation with adjacent vertebrae)

How many processes has each thoracic vertebrae?

7 processes

What is the difference between typical and atypical thoracic vertebrae in terms of number and position of costal facets on their bodies?

• Typical thoracic vertebrae(2-9) have both superior and inferior demifacets.

• Atypical thoracic vertebrae(1, 10-12) have whole costal facets and articulate with a single rib.

Describe the anatomy of a typical thoracic verterbrae

Describe the anatomy of the sternum

What are the parts of the Sternum?

Manubrium, Body and Xiphoid process

What is the shape of the sternal manubrium?

Roughly trapezoid

What part of the sternal manubrium is easily palpated?

The Jugular(suprasternal) notch

What is the vertebral level of the body of the sternum?

T5 - T9

What is the vertebral level of the manubrium?

T3 and T4

How many sternebrae form the body of a typical sternum?

4 sternebrae

What is the most variable part of the sternum?

Xiphoid process

What vertebral level does the Xiphoid process correspond to?

T10

What junction indicates the inferior limit of the central part of the thoracic cavity?

Xiphisternal joint

The Xiphoid is an important landmark in the median plane, why?

What are the boundaries of the thoracic wall?

• Anterior: Sternum

• Posterior: The 12 thoracic vertebrae and their intervertebral discs

• Lateral: The ribs, intercostal muscles and costal cartilages

• Roof: Suprapleural membrane

• Inferior: Diaphragm

What are the boundaries of the superior thoracic aperture?

• Posteriorly: T1 vertebrae

• Laterally: 1st pair of ribs and their costal cartilages

• Anteriorly: The superior border of the manubrium

What shape is the superior thoracic aperture?

Oblique, Kidney-shaped

Clinically the superior thoracic aperture is called?

Thoracic outlet

What is the diaphragm of the thoracic inlet?

Suprapleural membrane

Suprapleural membrane

What are the contents of the thoracic inlet?

Vessels (Brachiocephalic artery, left common carotid artery & left subclavian artery • Brachiocephalic veins • Thoracic duct)

Nerves (Vagus nerve • Phrenic nerve • Sympathetic chain • 1st Thoracic nerve)

Viscera (Apex of the lung and cervical pleura, esophagus, trachea)

What are the boundaries of the inferior thoracic aperture?

Anteriorly: Xiphoid process

Posteriorly: T12 vertebrae

Laterally: The last 6 costal cartilages and last rib

Inferiorly: Diaphragm

What is the costal arch(margin)?

What are the articulations of the manubrium?

What type of joint is the Xisphisternal joint?

Secondary cartilaginous joint(symphysis)

What type of joint is the Manubriosternal joint?

Secondary cartilaginous joint(symphysis)

What type of joint is the sternocostal joint?

Primary cartilaginous joint(synchondrosis)

Where is the weakest part of the rib?

Just anterior to the costal angle

Enumerate the joints of the thoracic cage and their types.

1. Intervertebral Joint ()

2. Interchondral joint ()

3. Sternocostal joint ()

4. Sternoclavicular joint ()

5. Costovertebral joint ()

6. Costochondral joint ()

7. Manubriosternal joint (Secondary cartiliganous-Symphysis)

8. Xiphisternal Joint (Primary cartilaginous-Chondrosis)

What are the three major types of joints?

Synovial, Fibrous and Cartilaginous joints

What are the the sub-types of the three main types of joints?

Synovial ()

Fibrous ()

Cartilaginous (Symphyses(Secondary) and Synchondroses(Primary))

At what week of development does the vascular system appear?

3rd week

What is a Zygote?

The single cell product of fertilization(fusion of male and female gamete)

What makes up the Digestive System?

GI Tract - Oral cavity(Mouth), Pharynx, Esophagus, Stomach, Small & Large Intestines, Rectum and Anus(Anal canal)

Accessory Glands- Salivary Glands, Pancreas, Gall Bladder, Liver

What are the main layers of the gastrointestinal tract wall?

• Mucosa

• Submucosa

• Muscularis externa

• Serosa/adventitia

What are the subdivisions of the GI mucosa?

• Epithelium

• Lamina propria

• Muscularis mucosae

What is the innermost layer of the digestive tract?

Mucosa(Mucous membrane)

Where is the muscularis mucosae found in the gastrointestinal tract?

It is found only in the tubular portion of the gastrointestinal tract.

What happens to the mucosa in the absence of submucosa?

The Mucosa is immobile and firmly attached to surrounding structures

Describe the histology of the digestive system

What is the composition of the lamina propria?

Loose connective tissue housing small blood vessels, lymphatics, leukocytes, and often small glands

What is the composition of the muscularis mucosae and its functional histology?

Smooth muscle that aid local movement of mucosa

Composition of submucosa layer?

The submucosa contains denser connective tissue with larger blood vessels, lymphatics, and the submucosal (Meissner) plexus of autonomic nerves.

Which layer of the GI tract wall is responsible for peristalsis?

Muscularis externa

What are the articulations of the head of the rib?

The superior costal facet of the rib numerically corresponding to it, The inferior costal facet of the rib above it and the IV disc between these two vertebrae

Describe the ligaments associated with the costotransverse joint.

Costotransverse ligament: The costotransverse ligament extends from the neck of the rib to the transverse process of the corresponding thoracic vertebra and strengthens the anterior aspect of the costotransverse joint.

Lateral costotransverse ligament: The lateral costotransverse ligament extends from the non-articular part of the tubercle of the rib to the tip of the transverse process of the corresponding thoracic vertebra and strengthens the posterior aspect of the costotransverse joint

Superior Costotransverse ligament: The superior costotransverse ligament extends from the crest of the neck of the rib to the transverse process of the vertebra above.