MD ARIFUL ISLAM PT DEPARTMENT OF PHYSIOTHERAPY LOVELY PROFESSIONAL UNIVERSITY PUNJAB INDIA.

1. Md. ARIFUL ISLAM
LOVELY PROFESSIONAL UNIVERSITY PUNJAB ,INDIA
ANATOMY OF BRAINSTEM
Description
The Brainstem lies at the base of the brain and the top of the spinal cord. It houses
many of the control centres for vital body functions, such as swallowing, breathing, and
vasomotor control. The 3 structures of the brainstem are coloured in diagram to right.
Structure
The brainstem is generally said to be composed of three parts. Components, from
above downward:
1. Midbrain (or Mesencephalon)
2. Pons (part of the metencephalon)

2. 3. Medulla AKA Medulla Oblongata (myelencephalon)
Midbrain:
This consists of 3 parts: the tectum, the tegmentum and paired cerebral peduncles.
These peduncles are the anterior part of the midbrain that connects the remainder of
the brainstem to the thalami. They are paired, separated by the interpeduncular cistern,
and contain the large white matter tracts that run to and from the cerebrum[1].The
substantia nigra lies in the cerebral peduncles.
Pons:
Consists of a posterior part, the tegmentum, and an anterior basilar part.
Medulla:
The "bulb" is an archaic term for the medulla oblongata, and in modern clinical usage the
word bulbar (e.g. bulbar palsy) is retained for terms that relate to the medulla oblongata.
The word bulbar can refer to the nerves and tracts connected to the medulla, and also by
association to the muscles thus innervated, such as those of the tongue, pharynx and
larynx.[2]

3. Anatomical Relations
The brainstem is located in posterior cranial fossa[3].
Above, the midbrain is continuous with the cerebral hemisphere. Below, the medulla is
continuous with the spinal cord.
Posteriorly, the pons and medulla are separated from the cerebellum by the fourth
ventricle.
Function
The brainstem has three broad functions:
1. Serves as a conduit for the ascending tracts and descending tracts connecting the spinal
cord to the different parts of the higher centres in the forebrain
1. Contains important reflex centres associated with the control of:
 respiration
 cardiovascular system
 consciousness
3. Contains the nuclei of Cranial Nerves III to XII.
The brain stem is responsible for, and regulatory of, the following functions of the
human body:
 Alertness
 Attention
 Arousal
 Breathing
 Heart rate
 Blood pressure
 Conveys information and signals shared between the peripheral nerves and spinal cord
to the upper brain

4.  Other autonomic functions such as digestion, salivation, perspiration, dilation or
contraction of the pupils, urination, etc.
Clinical Significance
A Stroke affecting the brainstem can cause severe symptoms which include:
 Problems with vital functions, such as breathing - frequently resulting in death
 Difficulty with chewing, swallowing, and speaking
 Weakness or paralysis in the arms, legs, and/or face
 Problems with balance or sensation
 Hearing loss
 Vision problems
 Vertigo
 Locked-in Syndrome
 Coma [4]