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NEET MDS Lessons
Anatomy

  • The six muscles rotate the eyeball in the orbit around three axes (sagittal, horizontal and vertical).
  • The action of the muscles can be deduced by their site of insertion on the eyeball.
Muscle Action(s) on the Eyeball Nerve Supply
Medial Rectus Adducts CN III
Lateral Rectus Abducts CN VI
Superior Rectus Elevates, adducts, and medially rotates CN III
Inferior Rectus Depresses, adducts, and laterally rotates CN III
Superior Oblique Depresses, abducts, and medially rotates CN IV
Inferior Oblique Elevates, abducts, and laterally rotates CN III

Hip

Constitutes the pelvic girdle
United with the vertebral column
Union of three parts that is marked by a cup shaped cavity (acetabulum) Ilium
•    Prominence of the hip
•    Superior border is the crest
•    Anterosuperior spine-projection at the anterior tip of the crest
•    Corresponding projections on the posterior part are the posterosuperior and posteroinferior iliac spines
•    Greater sciatic notch-located beneath the posterior part
•    Most is a smooth concavity (iliac fossa)
•    Posteriorly it is rough and articulates with the sacrum in the formation of the sacroiliac joint

Pubic bone

Anterior part of the innominate bone
Symphysis pubic-joining of the two pubic bones at the midline
Body and two rami 
•    Body forms one fifth of the acetabulum
•    Superior ramis extends from the body to the median plane: superior border forms the pubic crest
•    Inferior ramus extends downward and meets with the ischium
•    Pubic arch is formed by the inferior rami of both pubic hones

Ischium
    Forms the lower and back part of the innominate bone
    Body
•    Forms two fifths of the accrabulum
•    Ischial tuberosiry-supports the body in a sitting position
•    Ramus-passes upward to join the inferior ramus of rhe pubis; known as rhe obturator foramen

Pelvis

Fanned by the right and left hip bones, sacrum, and coccyx

Greater pelvis

o    Bounded by the ilia and lower lumbar vertebrae
o    Gives support to the abdominal viscera

Lesser pelvis

o    Brim of the pelvis corresponds to the sacral promontory
o    Inferior outlet is bounded by the tip of the coccyx, ischial tuberosities, and inferior rami of the pubic bones

Female pelvis

o    Shows adaptations related to functions as a birth canal Wide outlet
o    Angle of the pubic arch is obtuse

Male pelvis

o    Shows adaptations that contribute to power and speed
o    Heart-shaped outlet
o    Angle of the pubic arch is acute


Thigh

Femur-longest and strongest bone of the body
Proximal end has a rounded head that articulates with the acetabulum
Constricted portion-the neck
Greater and lesser trochanters
Slightly arched shaft; is concave posteriorly
o    Linea aspera-strengthened by this prominent ridge
o    Site of attachment for several muscles
Distal end has two condyles separated on the posterior side by the intercondyloid notch

Knee cap

Patella-sesamoid bone
Embedded in the tendon of the quadriceps muscle
Articulates with the femur


Leg

Tibia-medial bone
o    Proximal end has two condyles that articulate with the femur
o    Triangular shaft

    Anterior-shin
    Posterior-soleal line
    Distal-medial malleolus that articulates with the latus to form the ankle joint
Fibula-lateral bone
o    Articulates with the lateral condyle of the tibia but does not enter the knee joint
o    Distal end projects as the lateral malleolus


Ankle, foot, and toes

Adapted for supporting weight but similar in structure to the hand

Talus

o    Occupies the uppennost and central position in the tarsus
o    Distributes the body weight from the tibia above to the other tarsal bones
Calcaneus (heel)-Iocated beneath the talus
Navicular-located in front of the talus on the medial side; articulates with three cuneifonn bones distally
Cuboid-lies along the lateral border of the navicular bone

Metatarsals
o    First, second, and third p1etatarsals lie in front of the three cuneifonn bones
o    (2) Fourth and fifth metatarsals lie in front of the cuboid bone

Phalanges

o    Distal to the metatarsals
o    (2) Two in the great toe; three in each of the other four toes .

Longitudinal arches in the foot (2)

o    Lateral-fonned by the calcaneus, talus, cuboid, and fourth and fifth metatarsal bones
o    Medial-fonned by the calcaneus, talus, navicular, cuneifonn, and first, second, and third metatarsal bones

Transverse arches-formed by the tarsal and metatarsal bones

 

-> This bone forms much of the base and posterior aspect of the skull.
-> It has a large opening called the foramen magnum, through which the cranial cavity communicates with the vertebral canal.
-> It is also where the spinal cord becomes continuous with the medulla (oblongata) of the brain stem.
-> The occipital bone is saucer-shaped and can be divided into four parts: a squamous part (squama), a basilar part (basioccipital part), and two lateral parts (condylar parts).
-> These four parts develop separately around the foramen magnum and unite at about the age of 6 years to form one bone.
-> On the inferior surfaces of the lateral parts of the occipital bone are occipital condyles, where the skull articulates with C1 vertebra (the atlas) at the atlanto-occipital joints.
-> The internal aspect of the squamous part of the occipital bone is divided into four fossae: the superior two for the occipital poles of the cerebral hemispheres, and the inferior two, called cerebellar fossae, for the cerebellar hemispheres.

 

Muscles of the Soft Palate

The Levator Veli Palatini (Levator Palati)

  • Superior attachment: cartilage of the auditory tube and petrous part of temporal bone.
  • Inferior attachment: palatine aponeurosis.
  • Innervation: pharyngeal branch of vagus via pharyngeal plexus.
  • This cylindrical muscle runs inferoanteriorly, spreading out in the soft palate, where it attaches to the superior surface of the palatine aponeurosis.
  • It elevates the soft palate, drawing it superiorly and posteriorly.
  • It also opens the auditory tube to equalise air pressure in the middle ear and pharynx.

 

The Tensor Veli Palatini (Tensor Palati)

  • Superior attachment: scaphoid fossa of medial pterygoid plate, spine of sphenoid bone, and cartilage of auditory tube.
  • Inferior attachment: palatine aponeurosis.
  • Innervation: medial pterygoid nerve (a branch of the mandibular nerve).
  • This thin, triangular muscle passes inferiorly, and hooks around the hamulus of the medial pterygoid plate.
  • It then inserts into the palatine aponeurosis.
  • This muscle tenses the soft palate by using the hamulus as a pulley.
  • It also pulls the membranous portion of the auditory tube open to equalise air pressure of the middle ear and pharynx.

 

The Palatoglossus Muscle

  • Superior attachment: palatine aponeurosis.
  • Inferior attachment: side of tongue.
  • Innervation: cranial part of accessory nerve (CN XI) through the pharyngeal branch of vagus (CN X) via the pharyngeal plexus.
  • This muscle, covered by mucous membrane, forms the palatoglossal arch.
  • The palatoglossus elevates the posterior part of the tongue and draws the soft palate inferiorly onto the tongue.

 

The Palatopharyngeus Muscle

  • Superior attachment: hard palate and palatine aponeurosis.
  • Inferior attachment: lateral wall of pharynx.
  • Innervation: cranial part of accessory nerve (CN XI) through the pharyngeal branch of vagus (CN X) via the pharyngeal plexus.
  • This thin, flat muscle is covered with mucous membrane to form the palatopharyngeal arch.
  • It passes posteroinferiorly in this arch.
  • This muscle tenses the soft palate and pulls the walls of the pharynx superiorly, anteriorly and medially during swallowing.

 

The Musculus Uvulae

  • Superior attachment: posterior nasal spine and palatine aponeurosis.
  • Inferior attachment: mucosa of uvula.
  • Innervation: cranial part of accessory through the pharyngeal branch of vagus, via the pharyngeal plexus.
  • It passes posteriorly on each side of the median plane and inserts into the mucosa of the uvula.
  • When the muscle contracts, it shortens the uvula and pulls it superiorly.

  • U-shaped bone
  • Body
  • Greater horn
  • Lesser horn
  • Suspended by ligaments from the styloid process
 

The Arteries of the Face

  • The superficial arteries are derived from the external carotid arteries.

The Facial Artery

  • This is the chief artery of the face.
  • It arises from the external carotid artery and winds its way to the inferior border of the mandible, just anterior to the masseter muscle.
  • It hooks around the inferior border of the mandible and grooves the bone. Here the artery is superficial, just beneath the platysma and its pulsation can be felt.
  • In its course over the face to the medial angle of the eye, the facial artery crosses the mandible, buccinator muscle, and maxilla.
  • It lies deep to the zygomaticus major.
  • The facial artery ends by sending branches to the lip and side of the nose.
  • The part of the artery that runs along the side of the nose to supply the eyelids is called the angular artery.

The Superficial Temporal Artery

  • This artery is the smaller of the two terminal branches of the external carotid artery (the other is the maxillary artery).
  • It begins deep to the parotid gland, posterior to the neck of the mandible, and ascends superficial to the posterior end of the zygomatic process of the temporal bone. It then enters the temporal fossa.
  • The superficial temporal artery ends in the scalp by dividing into the frontal and parietal branches.
  • Pulsation of this artery can be felt by compressing the root of the zygomatic process of the temporal bone.

The Transverse Facial Artery

  • This small artery arises from the superficial temporal artery before it emerges from the parotid gland.
  • It crosses the face superficial to the masseter muscle, about a fingerbreadth inferior to the zygomatic arch.
  • It divides into numerous branches that supply the parotid gland and duct, the masseter muscle, and the skin of the face.
  • It anastomoses with branches of the facial artery.

  • The tongue is divided into halves by a medial fibrous lingual septum that lies deep to the medial groove.
  • In each half of the tongue there are four extrinsic and four intrinsic muscles.
  • The lingual muscles are all supplied by the hypoglossal nerve (CN XII).
  • The only exception is palatoglossus, which is supplied by the pharyngeal branch of the vagus nerve, via the pharyngeal plexus.

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